The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. I. Identifying and Characterizing the Protostellar Content of the OMC-2 FIR4 and OMC-2 FIR3 Regions

Tobin, John J.; Megeath, S. Thomas; Hoff, Merel L. R. van ’t; Díaz-Rodríguez, A. K.; Reynolds, Nickalas; Osorio, M. R. Zapatero; Anglada, Guillem; Furlan, Elise; Karnath, Nicole; Offner, Stella S. R.; Sheehan, Patrick; Sadavoy, Sarah; Stutz, Amelia M.; Fischer, William J.; Kama, M.; Persson, M. V.; Francesco, James Di; Looney, Leslie W.; Watson, D. M.; Li, Zhi Yun; Stephens, Ian; Chandler, Claire J.; Cox, Erin G.; Dunham, Michael M.; Kratter, Kaitlin M.; Kounkel, Marina; Mazur, Brian; Murillo, Nadia M.; Patel, Lisa; Pérez, Laura; Segura-Cox, Dominique; Sharma, Rajeeb; Tychoniec, Łukasz; Wyrowski, F.

doi:10.3847/1538-4357/ab498f

Cited by 30 publications

(58 citation statements)

References 92 publications

(195 reference statements)

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“…We make use of data from two ALMA bands, a single band of VLA data, and near-infrared spectroscopy in our study of HOPS-370. The ALMA 0.87mm observations and the VLA 9mm observations have already been detailed in Tobin et al (2019Tobin et al ( , 2020; we only briefly describe those observations. The new ALMA 1.3mm observations and near-infrared spectroscopic observations are described in more detail, along with their reduction procedures.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

“…The bandwidth and spectral resolution of the spectral windows were 937.5MHz with 0.489km s −1 channels and 234.375MHz with 0.128km s −1 channels. Additional details of the data reduction and imaging are provided in Tobin et al (2019Tobin et al ( , 2020. The data are available from the Harvard Dataverse (Tobin 2019a).…”

Section: Alma 087mm Observationsmentioning

confidence: 99%

“…Model fitting to its SED in the aforementioned paper indicates an internal luminosity of 511L e (values are adjusted to account for the adopted distance of 392 pc vs. the previously adopted 420 pc). 17 Thus, HOPS-370 is one of the most luminous protostars forming north of the Orion Nebula in the OMC2 and OMC3 regions (e.g., Tobin et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…HOPS-370 is also driving a strong jet and outflow that is seen in radio continuum (Osorio et al 2017), [O I] 63μm, far-infrared CO, and H 2 O lines (González-García et al 2016) and low-J CO (Williams et al 2003;Shimajiri et al 2008;Takahashi et al 2008;Tobin et al 2019). Furthermore, observations by the NSF's Karl G. Jansky Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array (ALMA) have observed the region with ∼0 1 resolution, resolving an apparent disk in the dust continuum and indications of rotation in methanol, H 13 CN, and NS (Tobin et al 2019). The combination of observational results toward this region from Tobin et al (2019), Furlan et al (2014), and Osorio et al (2017) indicates that HOPS-370 is a candidate intermediate-mass protostar with similar spectral properties to hot corinos (Ceccarelli 2004;Taquet et al 2015;Drozdovskaya et al 2016;Jacobsen et al 2018;Lee et al 2018).…”

Section: Introductionmentioning

confidence: 99%

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The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. IV. Unveiling the Embedded Intermediate-Mass Protostar and Disk within OMC2-FIR3/HOPS-370

Tobin

Sheehan²,

Reynolds

et al. 2020

ApJ

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We present ALMA (0.87 and 1.3 mm) and VLA (9 mm) observations toward the candidate intermediate-mass protostar OMC2-FIR3 (HOPS-370; L bol ∼314 L e) at ∼0 1 (40 au) resolution for the continuum emission and ∼0 25 (100 au) resolution of nine molecular lines. The dust continuum observed with ALMA at 0.87 and 1.3mm resolves a near edge-on disk toward HOPS-370 with an apparent radius of ∼100au. The VLA observations detect both the disk in dust continuum and free-free emission extended along the jet direction. The ALMA observations of molecular lines (H 2 CO, SO, CH 3 OH, 13 CO, C 18 O, NS, and H 13 CN) reveal rotation of the apparent disk surrounding HOPS-370 orthogonal to the jet/outflow direction. We fit radiative transfer models to both the dust continuum structure of the disk and molecular line kinematics of the inner envelope and disk for the H 2 CO, CH 3 OH, NS, and SO lines. The central protostar mass is determined to be ∼2.5M e with a disk radius of ∼94au, when fit using combinations of the H 2 CO, CH 3 OH, NS, and SO lines, consistent with an intermediate-mass protostar. Modeling of the dust continuum and spectral energy distribution yields a disk mass of 0.035M e (inferred dust+gas) and a dust disk radius of 62au; thus, the dust disk may have a smaller radius than the gas disk, similar to Class II disks. In order to explain the observed luminosity with the measured protostar mass, HOPS-370 must be accreting at a rate of (1.7−3.2)×10 −5 M e yr −1 .

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Section: Observations and Data Reductionmentioning

confidence: 99%

Section: Alma 087mm Observationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. IV. Unveiling the Embedded Intermediate-Mass Protostar and Disk within OMC2-FIR3/HOPS-370

Tobin

Sheehan²,

Reynolds

et al. 2020

ApJ

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The double signature of local cosmic-ray acceleration in star-forming regions

Padovani

Marcowith

Galli

et al. 2021

A&A

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Context. Recently, there has been an increased interest in the study of the generation of low-energy cosmic rays (< 1 TeV) in shocks situated on the surface of a protostar or along protostellar jets. These locally accelerated cosmic rays offer an attractive explanation for the high levels of non-thermal emission and ionisation rates observed close to these sources. Aims. The high ionisation rate observed in some protostellar sources is generally attributed to shock-generated UV photons. The aim of this article is to show that when synchrotron emission and a high ionisation rate are measured in the same spatial region, a locally shock-accelerated cosmic-ray flux is sufficient to explain both phenomena. Methods. We assume that relativistic protons and electrons are accelerated according to the first-order Fermi acceleration mechanism, and we calculate their emerging fluxes at the shock surface. These fluxes are used to compute the ionisation rate and the non-thermal emission at centimetre wavelengths. We then apply our model to the star-forming region OMC-2 FIR 3/FIR 4. Using a Bayesian analysis, we constrain the parameters of the model and estimate the spectral indices of the non-thermal radio emission, the intensity of the magnetic field, and its degree of turbulence. Results. We demonstrate that the local cosmic-ray acceleration model makes it possible to simultaneously explain the synchrotron emission along the HOPS 370 jet within the FIR 3 region and the ionisation rate observed near the FIR 4 protocluster. In particular, our model constrains the magnetic field strength (∼250−450 μG), its turbulent component (∼20−40 μG), and the jet velocity in the shock reference frame for the three non-thermal sources of the HOPS 370 jet (between 350 km s−1 and 1000 km s−1). Conclusions. Beyond the modelling of the OMC-2 FIR 3/FIR 4 system, we show how the combination of continuum observations at centimetre wavelengths and molecular transitions is a powerful new tool for the analysis of star-forming regions: These two types of observations can be simultaneously interpreted by invoking only the presence of locally accelerated cosmic rays, without having to resort to shock-generated UV photons.

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ORion Alma New GEneration Survey (ORANGES)

Bouvier

López-Sepulcre

Ceccarelli

et al. 2021

A&A

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Context. The spectral energy distribution (SED) in the millimetre to centimetre range is an extremely useful tool for characterising the dust in protostellar envelopes as well as free-free emission from the protostar and outflow. Actually, the evolutionary status of solar-type protostars is often based on their SED in the near-infrared to millimetre range. In addition, the presence or absence of free-free emission can be considered an indicator of the source evolutionary stage (Class 0/I versus Class II/III). While many studies have been carried out towards low- and high-mass protostars, little exists so far about solar-type protostars in high-mass star-forming regions, which are likely to be representatives of the conditions where the Solar System was born. Aims. In this work, we focus on the embedded solar-type protostars in the Orion Molecular Cloud (OMC) 2 and 3 filaments, which are bounded by nearby HII regions and which are, therefore, potentially affected by the high-UV illumination of the nearby OB stars. We use various dust parameters to understand whether the small-scale structure (≤1000 au) and the evolutionary status of these solar-type protostars are affected by the nearby HII regions, as is the case for the large-scale (≤104 au) gas chemical composition. Methods. We used the Atacama Large (sub-)Millimeter Array (ALMA) in the 1.3 mm band (246.2 GHz) to image the continuum of 16 young (Class 0/I) OMC-2/3 solar-type protostars, with an angular resolution of 0.25″ (100 au). We completed our data with archival data from the ALMA and VLA VANDAM survey of Orion Protostars at 333 and 32.9 GHz, respectively, to construct the dust SED and extract the dust temperature, the dust emissivity spectral index, the envelope plus disk mass of the sources and to assess whether free-free emission is contaminating their dust SED in the centimetre range. Results. From the millimetre to centimetre range dust SED, we found low dust emissivity spectral indexes (β < 1) for the majority of our source sample and free-free emission towards only 5 of the 16 sample sources. We were also able to confirm or correct the evolutionary status of the source sample reported in the literature. Finally, we did not find any dependence of the source dust parameters on their location in the OMC-2/3 filament. Conclusions. Our results show that the small-scale dust properties of the embedded OMC-2/3 protostars are not affected by the high-UV illumination from the nearby HII regions and that the formation of protostars likely takes place simultaneously throughout the filament.

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The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. I. Identifying and Characterizing the Protostellar Content of the OMC-2 FIR4 and OMC-2 FIR3 Regions

Cited by 30 publications

References 92 publications

The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. IV. Unveiling the Embedded Intermediate-Mass Protostar and Disk within OMC2-FIR3/HOPS-370

The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. IV. Unveiling the Embedded Intermediate-Mass Protostar and Disk within OMC2-FIR3/HOPS-370

The double signature of local cosmic-ray acceleration in star-forming regions

ORion Alma New GEneration Survey (ORANGES)

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