2019A A-ranked projects with tracks in the queue or complete
Project IDP.I.# TracksTitle (hover for abstract)
2019A-A004Hau-Yu Baobab Liu1
Millimeter Flux Variability/Stability of FU Orionis Objects and EXorsOur team has analyzed 40 tracks of SMA observations towards 29 young stellar objects which present accretion outbursts, namely the FUor, EXor, and FUor-like objects. Their >1 mm emission appears to have significant contribution from the hot (>300 K) inner disk (HID) of only a few AU scales. Only a few of these sources happened to be observed at the same frequencies and similar uv-coverage for multiple times, separated by from few months to a few years. We report tentative evidence of 1.33 mm flux variability from three of them: V2494 Cyg, V2495 Cyg, and AR 6A. We suspect that millimeter flux variability may not be uncommon among these outburst YSOs, however, was not being monitored by observatories with reasonably good absolute flux calibration. The flux variability may be related to the chaotic evolution of the HID, altered by their very massive and time varying accretion. We hereby take the initiative to monitor bright and compact sources which are available for the summer semester, and will follow-up the winter term sources in the next deadline.
2019A-A011Yuji Urata1
Search for Bright submm GRB afterglows Toward Radio PolarimetryBasis of our successful measurement of the first radio polarization for the GRB afterglow by the coordinated SMA and ALMA program, we propose continuation of (1) detecting bright submm GRB afterglows toward radio polarimetry, (2) decoding the radiation of afterglows for estimating the radiated energy in afterglow phase, and then (3) understanding diversity of GRB progenitor stars. In this program, we intend to conduct calorimetry of GRB including non-energized electron contribution with the radio polarization by coordinated SMA and ALMA observations. A 30 solar-mass progenitor star is typically used in long-GRBs models, in which all electrons are energized by the relativistic shock and emit the synchrotron radiation as afterglows. However, a substantial fraction of the electrons likely remains cool and emit non-observable radiation. These non-energized electrons increase the total energy and require a significant revision of the standard mass of progenitor star. As we demonstrated with previous programs, initial SMA rapid observations are crucial to identify bright submm GRB afterglows for the radio polarimetry and to decode complex radiation components.
2019A-A013Jia-Wei Wang3
Resolve the polarization morphology from the envelope to the Keplerian disk at 200 AU scale in the massive protostar Cepheus A HW2Magnetic fields are believed to play a crucial role in massive star formation; however, it is difficult to observe the magnetic fields in massive system, since most of the systems are several kpc away. Here we propose to measure the magnetic field in the circumstellar disk of the nearest (~700 pc) massive protostar system Cep A HW2 using 345 GHz continuum polarization with extended and very-extended configuration. The proposed observation can probe the polarization pattern at 200 AU scale, which is sufficient to resolve the D=660 AU Keplerian disk. This project aims to (a) probe the magnetic fields from envelope to disk in a massive protostellar system, and (b) resolve the polarization pattern within the inner disk to investigate whether the self- scattering is also important in massive system in the same way as in the low- mass systems.
2019A-A014Yusuke Aso3
Pilot Survey of Deuterated Molecules in Class 0 Protostars (resubmission)We propose SMA observations toward eleven Class 0 and six Class I protostars in N2D+ and N2H+ J=3-2 lines and other deuterated species. The purpose of this study is to verify relation between their D/H ratio and evolution of the protostars in the same cluster forming region. Our ALMA Cycle 3 observations have revealed evolutionary differences among the Class 0 sources. Seven of them have no counterpart at <70 um wavelengths, implying an earlier phase than the others. Furthermore different evolutionary phases in this "earlier Class 0" have been revealed by three of such no-counterpart sources. The youngest source shows no detectable disk, a highly collimated outflow, and strong CO freeze out, while the most evolved one is associated with a disk with a sharp edge at 240 au and an outflow with the widest opening angle. We plan to examine the D/H ratios and study relation between D/H and evolutionary phases derived from physical conditions. Our study is unique in the sense of the coherent sample sharing the same initial condition.
2019A-A018Chia-Lin Ko2
Abundance ratios of S-bearing molecules as an alternative probe of grain growthOur team members have recently proposed an astrochemical approach to diagnose dust grain growth in young stellar objects (YSOs) based on the observations of the abundance ratios of H2S, SO, and SO2(Harada et al. 2017). We request to apply this technique to the well-studied Class 0 YSOs NGC1333 IRAS4A1 and IRAS4A2, taking the advantage of the dual RX and the SWARM capabilities of the SMA. Towards these sources, our previous analysis of Stokes I spectral energy distribution (SED) found that there is no firm evidence of grain growth (Li et al. 2017), which appears contradictory to the suggestion of Yang et al. (2016) who argued that the detected dust polarization at 8-10 mm wavelengths is dominated by polarized scattered light. Since one cannot yet be sure about whether or not large dust grains can align with magnetic or radiation field in Class 0 YSOs, how much the detected dust polarization at 8-10 mm is contributed by aligned dust grains instead of scattered light is not yet certain. Since the dust scattering opacity is extremely sensitive to the maximum grain size, the request independent constraint on maximum grain size based on astrochemistry will greatly help resolving this controversy. This project will therefore improve our understanding on the two very important topics in the field of star-formation: the dust grain growth, and the detailed magnetic field morphology.
2019A-A020Tomohiro Yoshida1
ASIAA summer student program 2019AThis is a project for the 1st shift. CO(2-1) and 13CO(2-1) observation of NGC6822 KD24.
2019A-H002Goran Sandell2
The R Mon / NGC 2261 (Hubble's variable nebula) molecular outflowObservations with the PdB interferometer in CO and 13CO at high angular resolution have been interpreted as a Keplerian disk around an 8 Msun star. The authors support their mass estimate with analysis of optical spectra and SED modeling, which they claim confirms that R Mon is a B0 star. However, their analysis and interpretation is not only seriously flawed, it is wrong. Even though R Mon is known to drive a bipolar molecular outflow, drive an optical jet and illuminate the reflection nebula NGC 2261 (Hubble’s variable nebula), they completely ignore the outflow (which is close to the plane of the sky). In their SED modeling they assume that all UV radiation comes from the photosphere of a B0 star, i.e. ignoring accretion which is the main source of UV radiation. The optical spectra are heavily veiled and show no absorption features that can be used for spectral typing. They derive a stellar luminosity of 5,500 Lsun;, while the observed bolometric luminosity is only 1,000 Lsun;. We have recently mapped the R Mon outflow in CO(3-2) and 13CO(3-2) with 18" resolution using the single dish telescope APEX. These observations show a bipolar outflow with low velocities, ±5 km/s, suggesting that the outflow is almost in the plane of the sky. Long integration spectra in CO(2-1), 13CO(2-1) and C18O(2-1) towards R Mon show outflow wings even in C18O and wing emission from +3 to 16 km/s (systemic velocity +9.5 km/s). If this emission comes from a Keplerian disk < 2" in size we should not see it in a 28" beam. It could however be argued that the outflow is not launched from the disk, but further out, which appears rather implausible. Here we target the R Mon outflow in CO(2-1) and 13CO using the SMA in the compact configuration. This setup is ideal, because the SMA is sensitive to structures as large as 30", yet it provides a spatial resolution of ~3". This will allow us to probe the morphology of the outflow in much higher details than what can be done with a single dish telescope. We can see where the outflow is launched, and how the molecular outflow is related to the jet seen at optical wavelengths. Our setup also includes SiO, which is a good shock tracer. By doing a three point mosaic we can cover the whole fan shaped Hubble nebula and see how the blue outflow lobe interacts with the surrounding cloud. At high velocities the APEX data show that the blue-shifted outflow becomes more collimated and jet like and oriented almost straight north from the star, suggesting that the disk essentially east-west. This will become much clearer, when imaged with SMA, which has much better spatial resolution.
2019A-H003Jonathan Williams4
A Search for Water and Complex Organics around an Outbursting StarWe have found a remarkably rich molecular spectrum in the disk around an outbursting FU Ori object. This provides a special opportunity to study the composition of the evaporating ices in a planet forming region. We propose to carry out a line survey using the wide bandwidth of the SMA to search for water and complex organics.
2019A-S004David Clements3
A Rosetta Stone for Distant Dusty Star-Forming Galaxies: SERVS, Herschel and the SMAThe discovery of a substantial population of high redshift far-IR luminous objects through colour selection of '500-risers' in Herschel data has been a surprise and a challenge for current models of galaxy formation and evolution. Understanding this population is difficult since they are both rare and faint in the optical/near-IR. A clear view of the optical-to-far-IR SEDs of such objects, necessary for understanding their stellar mass, star formation history and much more, is thus lacking. The advent of the SERVS deep IRAC survey data, now cross matched to deep optical/near-IR data in the 4.5 sq. deg. of the XMM-LSS field, can provide the missing link in understanding this population if we can obtain cross identifications. SMA observations will allow this, even in cases where the Herschel sources are blends of multiple fainter sources. We here propose SMA observations of a complete flux limited sample of five 500-risers, to obtain cross-IDs and thence to determine the full SEDs and stellar properties of these important but poorly understood objects.
2019A-S005Justin Spilker3
A Complete Inventory of the Molecular ISM in a Starburst Galaxy at the Peak Epoch of Cosmic Star FormationWe propose to showcase the power of the ultra-wide bandwidth of the SMA by performing a first-of-its-kind molecular line survey in the distant universe. Our target is an ultra-bright submillimeter galaxy at z~2, near the peak epoch of cosmic star formation, lensed by a foreground massive cluster. We expect to detect ~30 lines of 14 species that trace the full range of excitation conditions, ISM heating and cooling mechanisms, inflow/outflow and dynamical signatures, and chemical enrichment pathways. The wide bandwidth makes the SMA competitive with ALMA in these observations. Combined with existing observations of lower-frequency transitions of CO and CI, these SMA observations will stand as the definitive view of the ISM conditions in a z~2 starburst galaxy, serving as an effective comparative study to local starbursts observed with the Herschel/SPIRE-FTS instrument.
2019A-S008Todd Hunter2
Accretion outbursts in massive protostars: Monitoring of dust continuum and excited methanol masers in the third known source - G358.931-0.030The recent identification of extraordinary accretion outbursts in two high-mass protostars (NGC6334I and S255IR-NIRS3), were both heralded by the flaring of the Class II 6.7 GHz methanol maser line. Because Class II masers are radiatively pumped by infrared photons, they will closely follow the increase in luminosity of massive protostars in response to a sudden increase in accretion rate. These discoveries have rapidly impacted the traditional view of massive protostellar evolution, leading to new hydrodynamic simulations that can produce such episodic outbursts. The contrast in magnitude and decay timescales of these events demonstrates that these outbursts can have different properties, similar to outbursts in low-mass protostars. Thus the study of additional cases is of paramount importance to understand the underlying mechanism. In mid-January 2019, the 6.7 GHz Class II CH3OH maser line began flaring in the high mass protostellar object (HMPO) G358.931-0.030, making it the third known outburst in such objects. Our initial SMA filler observations in February 2019 provided the earliest millimeter imaging of such an outburst, giving us the first measurements of such an event during the initial rise in luminosity. Surprisingly, these observations yielded the first ever detection of several torsionally-excited methanol masers. In order to follow the evolution of accretion luminosity, we need to construct the light curve of the dust continuum emission and of the new (sub)millimeter methanol masers. This goal will be achieved by repeating our pending 2018B DDT observations in the 2019A semester.
2019A-S009Alexandra Tetarenko3
Constraining Jet Formation and Evolution with Transient X-ray BinariesRelativistic jets are launched from accreting black holes (BHs) on all scales, from stellar-mass BHs in X-ray binaries (BHXBs) to supermassive BHs in active galactic nuclei (AGN). BHXBs provide ideal laboratories for probing these jet phenomena due to their rapid (day-week) evolutionary timescales. In particular, broad-band spectral measurements of jet emission in Galactic BHXBs constrain the structure and physical conditions in the jet, where the mm/sub-mm regime bridges a crucial gap between radio and IR frequencies. However, only a small number of BHXBs have measurements sampling the mm/sub-mm regime across different states of an outburst. We propose targeting the next BHXB in outburst (> 5 mJy) with SMA ToO observations to accurately measure the evolving mm/sub-mm flux and constrain the broad-band spectral energy distribution in outbursting BHXBs. These observations will act as a continuation of our team's successful mm/sub-mm ToO research program with the SMA.
2019A-S011Mark Gurwell2
Full Polarization Thermal Mapping of Ganymede and CallistoAn archival program to calibrate the lightcurve of Ganymede using the SMA shows that Ganymede has an average brightness temperature of ~100 K, with a roughly 10 K difference between the leading and trailing hemispheres. In contrast Callisto has no discernable light curve. We propose to image Ganymede and Callisto at high spatial resolution in the 870 micron window, using the full dual band polarization capability of the SMA. These images will allow us to (a) map the polarization signature across the surface of both moons, which is a sensitive measure of surface and subsurface parameters such as the surface dielectric constant, roughness and absorption coefficient, and (b) map the suspected strong variation in brightness temperature across the disk of Ganymede, and verify the low variation of Callisto. The results of these observations have implications for our understanding of the thermal and material properties of the (sub)surfaces of the two largest moons in the Jovian system, as well as serve as benchmarks for the mm/submm flux density calibration models at use at the SMA and ALMA.
2019A-S016Henrik Beuther5
The importance of magnetic fields for the fragmentation of high-mass star-forming regions (the summer targets)Which processes dominate the fragmentation and cluster formation during the build up of the most massive stars? To address this question we are conducting an IRAM NOEMA large program to study how fragmentation and disk formation occur during the star formation process for 20 high-mass star-forming regions (CORE project, PI H. Beuther, Interestingly, we find a large variety between highly fragmented regions (up to 20 sub-cores) and regions that are dominated by one massive core. However, the crucial missing link of this project is that we do not have the corresponding magnetic field information (only 3 sample regions had been observed with the SMA in the past) and the regions are so northern that they are not available to ALMA. Since four regions were observed during the ongoing winter term, and three more are pending in the queue (see proposal history), we want to observe the remaining 13 regions with the SMA in the polarized dust continuum emission at 875mum in the compact configuration (split over several semesters because of the broad range in LST). Our primary goal is to study, via the polarized dust continuum emission, the magnetic field properties of this well-selected sample of high-mass star-forming regions. We will (a) estimate the magnetic field strength via the Davis-Chandrasekhar-Fermi method (taking into account the spatial filtering of the interferometer), (b) characterize the magnetic field morphology using the angle dispersion function, and (c) quantify the relative orientation between the magnetic field and the dense gas structures using the histogram of relative orientations. Comparing the magnetic field with the clustering properties obtained from the NOEMA observations, we will constrain whether magnetic fields are responsible for the observed fragmentation diversity. With these data, we can also investigate two complementary goals. One will be the study of the magnetic field via the Goldreich-Kylafis effect in the CO(3-2) line toward the outflows of the regions. This will address how well the outflow magnetic field is connected to the field observed in the dense gas via the dust polarization. A second complementary goal will be to dissect the chemical properties of the sample because we will observe a plethora of spectral lines over the broad bandpass of 16GHz.
2019A-S019Meredith MacGregor4
The Origin and Impact of Flares in M Dwarf SystemsM dwarf stars are the most abundant stars in the galaxy and have a high frequency of Earth-sized planets, making them the favored targets of upcoming missions to detect and characterize exoplanets. However, these stars are known to exhibit high levels of activity and flaring, which can deplete a planet's atmosphere of ozone over time, raising questions about the habitability of planets around these stars. There is still much to be learned about M dwarfs, their activity, and the potential habitability of their planetary systems. Since stellar activity at millimeter wavelengths remains largely unexplored, we propose to obtain SMA observations of two well-known flare stars to constrain the properties of detected flares. The combination of the SMA with TESS provides a unique, limited-time opportunity to accomplish multi-wavelength observations.
2019A-S021Howard Smith3
SMA Continued Participation in Simultaneous Monitoring of Flaring from the Galactic Center’s Supermassive Black Hole We propose three tracks of 235+345GHz observations of the variable emission from SgrA*, the supermassive black hole at the Galactic center, to be scheduled simultaneously with already awarded Spitzer and Chandra time. The submm dataset anchors the longwavelength behavior and helps discriminate between alternate model explanations, e.g., gravitational lensing effects of the accretion flow or cooling times of an emitting plasma. Although some early studies of SgrA* found that the submm flares follow NIR flares by about 90 minutes, we now have two campaigns with SMA flares that preceded the NIR. We continue to work with the R. Narayan group on theoretical modeling. The SMA submm data help establish the relationship between the flares, determine the wavelength dependence of the variable emission, and probe the physical processes at work. This is the final year of Spitzer and our last chance to observe simultaneously with it.
2019A-S025David Jewitt2
Extraordinary Distant Comet C/2017 K2Extraordinary long-period comet C/2017 K2 (PANSTARRS) ("K2") has a slightly hyperbolic orbit (e = 1.00035), inclination i = 88 deg and is approaching perihelion at 1.809 AU in 2022 December. It is believed to have passed through the planetary region 3 Myr ago and was perturbed from an initially bound (e < 1) orbit, originating in the Oort cloud, into an unbound one by planetary gravitational perturbations. K2 is unique in showing optical activity out to 26 AU, where the blackbody temperature is only 55 K. The largest distances at which cometary CO has been detected to date are about 6 AU, for both short-period 29P and famous long-period comet C/Hale-Bopp. Early detection of K2 at the current distance (12 AU) will offer us the unprecedented opportunity to examine the rise of activity in an uncharted zone. If detected either in the continuum or in CO, K2 would be by far the most distant comet ever detected, setting new constraints on the mechanism behind the activity.
2019A-S027Nacho Añez3
What is controlling the fragmentation process?The detailed process of the fragmentation of a high mass core to form a cluster is not well understood yet, and additional ingredients competing with gravity like turbulence, angular momentum, magnetic field and stellar feedback must play an important role. We selected two hubs of the Infrared Dark Cloud G14.225-0.506, apparently identical but with different fragmentation level, to investigate the role of the magnetic field during the fragmentation process. We propose to observe the 0.8 mm polarized dust emission at ~1.5" toward each hub. Our goals are: i)To investigate the magnetic field properties at different scales, from several tens of parsec (based on optical, near-IR and submillimeter polarization data) to the sub-parsec scale provided by the SMA. ii)To obtain the magnetic field in the plane of the sky and evaluate the contribution of each physical agent that play a role in the dynamical evolution of the regions.Sensitive SMA observations will provide a unique view of the magnetic field properties into a region close to the initial conditions of fragmentation allowing us to elucidate whether the magnetic field is responsible for the different fragmentation level.
2019A-S055Andrew Burkhardt4
A Deep, Broadband Interferometric Chemical Survey of L1157Astrophysical shocks substantially alter both the physical conditions and the molecular reservoir in forming protostellar systems, but these effects are not yet well-understood. Nowhere is this seen more clearly than in the prototypical chemically active shocked outflow L1157, whose blue-shifted lobe has been the subject of significant single-dish surveys and targeted interferometric observations. Neither approach, however, is able to fully explore how the morphology, excitation, and chemical complexity intertwine to produce the observed emission. Building on previous observations and modeling, we propose to perform the broadest interferometric molecular survey of L1157 to date to test the predictions from new chemically complex shock chemistry models. In 28 on-source hours, we can achieve the same sensitivity and spectral resolution as previous interferometric surveys, but at a significantly higher spatial resolution and, most importantly, across an unprecedented 32 GHz (non- contiguously between 217-268 GHz) enabled by the SWARM correlator. This will, in turn, act as a pilot study to expand this survey out the full spectral capabilities of the SMA.
2019A-S058Anna Ho6
The death throes of massive stars, revealed through early millimeter observationsIt has long been appreciated that mass-loss determines the fate of massive stars. However, mass-loss rates are poorly known, and matters are complicated by the recent recognition of massive outbursts preceding the collapse of the star. Fortunately, mass-loss is encoded in the circumstellar environment, which can be probed using long-wavelength (centimeter+millimeter) observations. The increased sensitivity of the SMA, combined with on-going radio studies with the VLA and AMI and the ready supply of young supernovae from optical surveys (ZTF, ATLAS), makes it a suitable time to start a program to investigate and study the innermost circumstellar environment, and thus the most recent mass-loss. Here, we propose to use the SMA study mass-loss at two extremes: massive stars with exotic endings (AT2018cow) and the nearest core-collapse supernovae.
2019A-S064Keping Qiu2
Continuum emission from massive starless coresHow massive stars form remains an open question in astrophysics. A key question in the context is about the initial conditions of massive star formation; it is so far unclear whether a high-mass prestellar core, which is presumably a self-gravitating molecular cloud core with a size of ~0.1 pc and a mass reaching 100 solar mass, is a prerequisite for the formation of massive stars. We have detected a sample of starless cores in the NH2D line with the NOEMA in the 3 mm waveband. These cores have very narrow (<1 km/s) line widths, but are all located near active high-mass star-forming cores. They are apparently cold, and thus faint in dust continuum emission, not detected in the NOEMA 3 mm continuum observations. Considering a high gas density required to excite NH2D emission, and the size of the cores, we expect to detect the dust continuum in the 1 mm waveband with an RMS sensitivity of 0.3 mJy/beam with the SMA. Here we request the SMA Subcompact and Compact observations under PWV < 2.5 mm.

2019A B-ranked tracks with successful observations:
Project IDP.I.# TracksTitle (hover for abstract)
2019A-S063Mark Gurwell9
Titan 1.1mm Band Spectral Line Imaging Survey We seek to revolutionize our inventory of molecular species in the atmosphere of Titan, capitalizing on the new broad bandwidth SWARM provides. We propose a 32 GHz continuous spectrum, moderately spatially resolving Titan, covering 247 to 279 GHz. While many species previously detected will be covered in this tuning (HCN and isotopologues, CH3CN, H3CN, CH3C2H, HNC, C2H5CN, etc), it will also cover dozens to hundreds of lines from heavier molecular species such as pentadiynenitrile (HC5N), vinyl cyanide (C2H3CN), adenine (C5N5H5), guanine (C5N5H5O), thymine (C5N2H6O2), glycine (C2NH5O2), and alanine (C3NH7O2), to name just a few. Many of these heavier species are precursors to and important for biological systems. While individual lines of such species may be undetectable at our noise goal, we can use spectral stacking at the known frequencies of the lines to increase our sensitivity by factors of up to 10 for some species. Due to the fact that these species are optically thin, the majority of their observed emission will appear near the disk limb. Therefore, it is advantageous to resolve Titan to emphasize this emission. Since Titan is ~0.8" in diameter (considering the mid-stratospheric height of limb sensitivity), this requires VEX configuration. To be certain we are obtaining a good global flux spectrum, we also need low resolution (COM) observations to anchor the imaging. Due to the well known structure of Titan's continuum, we will be able to phase and amplitude self-calibrate our data, lessening our weather stability requirements. An excellent byproduct of these observations will measurements of the latitudinal and vertical abundances of the strongly detected species, along with direct detection of stratospheric winds on Titan through measurement of Doppler shifts in the strong cores of molecular lines of HNC, HCN, and CH3CN. While this was recently done using ALMA (Lellouch, Gurwell et al 2019) from 2016, Titan's circulation pattern changes on seasonal timescales, and the 3 year span since those observations represents a significant seasonal change given Titan's 29.5 year orbit. Therefore, these SMA observations will be uniquely interesting and noteworthy. We request 45 hours on source (roughly 2 tracks in COM and 7 in VEX assuming 5 hours on source per track), in ~2.5mm pwv conditions to reach 6 K per beam rms per 140 kHz channel, at 0.5"x0.4" resolution, moderately resolving the 0.8" disk. Per beam, 6K rms/channel will allow for excellent measurements of Doppler shifts since these pressure broadened lines are typically 30-100 K in emission and will span several channels. For detection of weak species, binning to 1.12 MHz will give rms of 2 K per channel, with spectral stacking allowing even more effective noise suppression, perhaps down to 0.2-0.5 K for some species. Given the 70 K continuum temperature of Titan, these effective noise levels provide unprecedented sensitivity *even compared to ALMA*. The combination of comprehensive continuous coverage over 32 GHz, access to many lines, fine spectral resolution, and sensitivity, has never been achieved and will provide a rich data set from which to measure the molecular inventory of Titan's stratosphere.
2019A-S006Charles Law5
Searching for Ionized Accretion Flows around 0.1 pc Scale Clusters with O-Type StarsEarly O-type stars must gain tens of Msun after the onset of an HII region excited by their own radiation. How mass accretion takes place in the presence of strong outward thermal pressure during the HII region phase is a mystery. Our studies of a hyper compact HII region G10.6 demonstrate that such an accretion occurs in ionized gas and is driven by the gravitational pull of the massive star or a cluster of stars. This proposal seeks observations in a set of millimeter hydrogen recombination lines in a sample of hyper compact HII regions similar to G10.6 to search for and spatially resolve the accretion flow. This study will provide important clues to the formation of the most massive stars in the Universe.
2019A-S045Tomasz Kaminski2
What is K4-47? Investigating the Most Molecularly Complex Planetary Nebula to DateK4-47 was long thought to be an ordinary planetary nebula. Recent single-dish millimeter observations revealed however that it is unusually rich in complex molecules and istotopologues of, otherwise rare, CNO isotopes. The isotopic ratios are so unusual that it is difficult to classify K4-47 or explain its origin. It may be a product of an unexplored eruptive mechanism occurring in an aging stellar interior or a remnant of a recent stellar merger. We propose to use the SMA in an extended configuration to map its molecular emission for the first time. In this exploratory mapping project we would like to investigate the relative distribution of strongest 12C- and 13C-bearing molecules and look for lines of AlF. Detection of the latter may open a way to detect the radioactive isotope of 26Al in the future. Maps of the less exotic species will be used to asses the optical depth and fractionation effects on the measured isotopic ratios.
2019A-S031Matthew Ashby2
The Impact of Radio Jets on Star Formation in AGN Host GalaxiesPanchromatic SED modeling by Podigachoski et al. (2015) revealed intriguing hints of a possible causal connection between radio jet age (a proxy for AGN age) and star formation (SF) in powerful high-redshift radio galaxies. Specifically, SF in the hosts of long-lived radio-loud AGNs is systematically low, compared to that in the hosts of young AGNs. If confirmed, this would be strong new evidence for AGN feedback (e.g., Croton et al. 2006; Cresci & Miaolino 2018). Here we propose a first test of this idea with a pilot study to characterize the disks in four radio-loud AGNs from Podigachoski et al: two with short, young jets (3C 124 and 3C 298) and two with extended, mature jets (3C270.1 and 3C 297). We will combine the SMA measurements with our existing Spitzer(IRAC/IRS/MIPS), Herschel (PACS/SPIRE), and radio-frequency data to disentangle the contributions to the galaxies' luminosity. In this way we will determine whether the hosts of the older jets still contain or have instead exhausted their reservoirs of molecular gas, the fuel for SF, as traced by the thermal dust continuum (and possibly CO).
2019A-S044Tomasz Kaminski3
The aftermath of a stellar collision in the Galactic BulgeEWS 2002-BLG-360 (or BLG-360) belongs to a rare class of objects known as red novae which erupt in stellar-merger events. They give us a chance to study most catastrophic forms of binary interaction of non-compact stars, including the common-envelope phase understanding of which is central to modern astrophysics. We propose to obtain spectral and continuum flux measurements of BLG-360 which is the least studied of the five known Galactic red-nova remnants. The SMA has recently detected it for the first time as a millimeter-wave source. The requested fellow-up measurements will constrain the gas and dust content in the merger remnant and will provide basis for imaging of the merger site with ALMA at longest baselines. This project is part of a larger program aiming to explain why and how non-compact stars merge.
2019A-S059Michael McCollough4
Using SMA to probe the jet emission in microquasar Cyg X-3 during radio outburst Cygnus X-3 is a unique X-ray binary (XRB) with a Wolf-Rayet star for a mass-donating companion. It is relatively bright in the radio virtually all of the time and is shown to undergo giant radio outbursts (up to 20 Jy) with associated jet-like structures moving away from Cygnus X-3 at 0.3-0.9c. This last characteristic makes Cygnus X-3 a member of a subclass of XRBs called "microquasars" which are similar to quasars/AGNs in that they exhibit highly collimated relativistic jets. We are proposing to make a series of short daily SMA observations starting at the beginning of a major flare and to follow its evolution. This will allow us to probe the spectral and structural evolution of flare as well as be part of a larger multi-frequency campaign to examine the spectral energy distribution of major radio flares in Cygnus X-3.
2019A-H004Mark Gurwell1
UH RADAR PROGRAMThis project is set to account for the UH RADAR program for bird counting, requiring the SMA to protect the receivers and not observe.

Current or completed Large Scale Programs spanning ALL semesters:
Project IDP.I.# TracksTitle (hover for abstract)
2012B-S097Qizhou Zhang3
Star Formation in the Central Molecular ZoneThe inner 500 pc of our Galaxy, known as the central molecular zone (CMZ), is a star-forming environment with very extreme physical properties. Despite its large reservoir of dense gas that could form massive stars and clusters similar to the starbursts seen in galaxies, CMZ has a star formation rate a factor of 10 lower than the Schmidt-Kennicutt law. Because of the heavy extinction in the optical and infrared wavelengths, however, existing observations may miss a deeply embedded protostellar population. To investigate this scenario, we conducted a mini-survey with the SMA towards a sample of dense clouds with highest star formation potential, i.e. surface density >10^24 cm^-2 in CMZ at 280 GHz. The data reveal that most of them present compact dust continuum peaks possibly from protostellar cores. Are these peaks associated with embedded protostars? How do they compare with normal molecular cores in the Galactic disk? To address these questions, we propose to observe them in the 230 GHz band, to test protostellar nature of these objects via abundant molecular lines in this band. The SMA data will be supplemented with continuum and NH3 lines datasets obtained from the VLA. This is a pilot program to a large scale SMA project that images a significant area of the CMZ to census a population of deeply embedded protostellar objects. A lack of current star formation in the CMZ challenges a well established star formation (Schmidt-Kennicutt) law. The SMA observations play a unique role in solving this puzzle by probing young stellar populations that are possibly hidden from optical and IR observations due to heavy extinction, as well as radio continuum observations due to a lack of HII regions.
2013A-S079Michael Dunham3
(p)MASSES: (pilot) Mass Assembly of Stellar Systems and their Evolution with the SMAStars are assembled in molecular clouds through the gravitational collapse of dense cores of gas and dust. The final masses of stars are set during the protostellar stage by the complex interaction of many interrelated physical processes, including the underlying core mass function, core and disk fragmentation, the formation and evolution of protostellar disks, and mass-loss through direct ejection of jets and entrainment of surrounding material in molecular outflows. Several key questions related to the growth of stars and origins of the stellar initial mass function (IMF) are yet to be answered, including: (1) When, where, and how do cores and disks fragment into multiple systems? (2) What role do disks play in the transfer of mass from cores to stars? (3) To what extent do outflows regulate the protostellar mass accretion process? To answer these questions, we propose to conduct a 230 and 345 GHz, continuum and molecular line emission survey of a large sample of protostars in the nearby Perseus molecular cloud. Here we submit a small, pilot study of 4 targets in order to determine necessary sensitivities, verify our technical setup, and demonstrate the validity of our observations in answering the key science questions motivating this program.
2013B-S091Eric Keto61
CMZWe propose to exploit the SMA's unique combination of large primary beam, high angular resolution, and large instantaneous bandwidth to conduct the first sub-pc scale survey of the largest reservoir of dense gas in our Galaxy -- the central molecular zone (CMZ), the inner 500 pc of the Milky Way. This survey of the mm continuum and spectral line transitions will provide: (i) a complete census of the most massive and dense cloud cores; (ii) the location, strength and nature of strong shocks; (iii) the relationship of star formation to environmental conditions such as density, shocks, and large-scale flows. The high angular resolution of the SMA is necessary to find the highest density gas and image the distribution of shocks within individual star- forming clouds. The survey seeks to address fundamental open questions about the CMZ. What are the environmental conditions that lead to the formation of the most massive stars ($>$100 \Msun)? How do mass and energy flows shape the CMZ, regulate star formation, and control the activity of the central supermassive black hole? This survey will not only address immediate science goals but also provide a resource for future studies. Insofar as the CMZ resembles the central regions of other barred spiral galaxies, starburst galaxies in a quiescent phase, and the highly dense and energetic environment expected in galaxies in the early universe, this data set can be used as our nearest proxy for these environments.
2014A-S093Michael Dunham55
MASSES: Mass Assembly of Stellar Systems and their Evolution with the SMAStars are assembled in molecular clouds through the gravitational collapse of dense cores of gas and dust. The final masses of stars are set during the protostellar stage by the complex interaction of many interrelated physical processes, including the mass infall rate, core and disk fragmentation, ejection from multiple systems, the formation and evolution of protostellar disks, and mass-loss through jets and outflows. Several key questions related to the growth of stars and origins of the stellar initial mass function (IMF) are yet to be answered, including: (1) When, where, and how do cores and disks fragment into multiple systems? (2) What role do disks play in the transfer of mass from cores to stars? (3) To what extent do outflows regulate the protostellar mass accretion process? To answer these questions, we propose to conduct a 230 and 345 GHz, continuum and molecular line emission survey of all 73 protostars in the nearby Perseus molecular cloud. Our program will enable significant progress in answering all three of these questions and ultimately determining how stars are assembled from the surrounding dense gas.
2017A-S060Garrett "Karto" Keating27
The Millimeter-wave Intensity Mapping Experiment (mmIME)Molecular gas is central to the formation of stars in galaxies, but at high redshift, it has been well-studied in only a handful of the most luminous systems. Recent surveys with ALMA have hinted at a significant population (larger than theoretically expected) of molecular gas-rich (i.e., CO-bright) main sequence-like galaxies at high redshift, although these surveys have been limited in volume. While instruments like ALMA afford incredible sensitivity and resolution for performing studies of individual systems, it is suboptimal for blindly surveying for such objects over the large volumes required to reduce the impact of cosmic variance and sampling biases. We instead propose to use the SMA, whose larger bandwidth and primary beam make it more well-suited for a blind, large volume survey, covering a total area of ~100 sq. arcmin, between 195-203/211-219/227-235 GHz, within four regions within areas that are rich in multi-wavelength data sets. With these observations, we will use direct detection, stacking, and intensity mapping techniques, which will allow us to probe the abundance and physical properties of molecular gas in galaxies in a volume of nearly a million cubic megaparsecs. The proposed measurement will additionally leverage line intensity mapping efforts with both VLA, ACA, and ALMA, enabling cross-correlation between a multitude of line species. Relevant SMA Publications ------------------------- No SMA publications to date, as our first observations were completed in Feb 2016. Analysis of these data is on-going, and we are presently finalizing our results for publication. We expect to submit said publication in September/October 2017. Summary of Relevant Pilot Projects ---------------------------------- Proposal is a large-scale continuation of 2016B-S044, and is the successor to a recently completed intensity mapping experiment with CARMA. This proposal leverages two existing programs: a large-scale campaign with VLA at 1cm, and a recently completed (Cycle 4) 40-hour program with the ACA at 3mm. We also plan to propose for additional time with ACA and VLA, which will require cross- correlation with SMA data to fully enable the science potential of new data with these instruments. This proposal additionally builds off of two separate awards: one archival study focused on searching SMA calibrator fields for blind detections of spectral line emission from high-redshift objects, and one technical study looking at the feasibility of daytime observing with the SMA. The calibrator study, which is being conducting by the PI Keating and M. Fuchs, has made steady progress towards the development of a software pipeline, capable of digesting calibrator data and producing -- from a variety of instrument setups and array configurations -- bandpass, gain, and spectral SEFD/flux correction factors, with the goal of automatically being capable of producing calibrated image cubes for all calibrator observations performed by the SMA. At the time of proposal submission, we estimate that the first version of this pipeline will be ready to deploy in September 2017. The daytime observing project, which is also being led by the PI (with significant help from numerous members of the SMA staff), has also made significant progress in the past 6 months, and early tests seem to indicate that the array may be capable of operating up to 22 hours a day under "normal" weather conditions. One significant factor that was limiting daytime observations -- the degradation of pointing during post-sunrise observations -- has already been solved, allowing for generally good array performance until approximately noon HST (i.e., 18 hours of observations a day). Progress is now underway looking at methods for realtime phase correction and improved bandpass calibration techniques, as well as isolating sources of crosstalk/coupling within the system. We anticipate these efforts to offer improved observing capabilities moving forward toward the proposed observations, although we have estimated our time/sensitivity requirements with what we believe to be feasible at the time of proposal submission.
2017B-S075Jan Forbrich12
SMA Survey of Resolved Dust and Simultaneous CO Observations of GMCs in M31We propose a powerful and unique SMA survey to detect and resolve dust continuum emission in a large population of (~100) Giant Molecular Clouds (GMCs) in the famous Andromeda galaxy M31. As demonstrated in our pilot study, the SMA wideband upgrade is now enabling resolved interferometric dust continuum detections of individual GMCs in M31 at 230 GHz, the first such detections beyond the Magellanic Clouds. Our observations will provide the most robust, dust-derived measurements of the physical properties of GMCs within an external disk galaxy. We also propose to acquire simultaneous observations of 12CO(2-1) and 13CO(2-1) emission to measure the gas content of the GMCs with identical uv coverage. We will combine these measurements to characterize the fundamental physical properties of the GMC population across M31 to a degree only comparable in many key aspects to Milky Way studies. This project will enable much high-impact science including: 1) high-fidelity measurements of the GMC masses and shapes leading to an improved GMC mass function in M31, 2) direct measurements of the infamous CO "X" factor in individual GMCs and its variation across the galaxy, 3) a significantly improved assessment of Larson's scaling relations in M31 GMCs, and 4) a detailed assessment of cloud-scale star formation laws in M31, utilizing extensive existing multi-wavelength data. These results will provide an important calibration for the use of CO observations in deriving basic gas and star formation properties of external galaxies. Additional science goals include an assessment of dust emission vs optical extinction in M31. The survey will provide a unique SMA legacy that will remain unsurpassed for many years, in particular exceeding what can practically be done with ALMA due to the combination of wideband sensitivity and nearby distance of this northern target.