THE BOLOCAM GALACTIC PLANE SURVEY. X. A COMPLETE SPECTROSCOPIC CATALOG OF DENSE MOLECULAR GAS OBSERVED TOWARD 1.1 mm DUST CONTINUUM SOURCES WITH 7.°5 ⩽
                    <i>l</i>
                    ⩽ 194°

Shirley, Yancy L.; Ellsworth-Bowers, T. P.; Svoboda, Brian; Schlingman, W. M.; Ginsburg, Adam; Rosolowsky, Erik; Gerner, T.; Mairs, Steve; Battersby, Cara; Stringfellow, Guy S.; Dunham, Miranda K.; Glenn, J.; Bally, John

doi:10.1088/0067-0049/209/1/2

Cited by 66 publications

(114 citation statements)

References 61 publications

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“…Dunham et al (2011b) observed 631 BGPS sources within narrow ranges in Galactic longitude, while the new data presented in this work observed BGPS clumps that were detected in dense gas tracer HCO + 3-2 and had T pk (HCO + ) > 0.3 K from Schlingman et al (2011) and Shirley et al (2013). All new observations were targeted with the center pixel of the K-band Focal Plane Array (KFPA) toward the S 1.1 mm flux density peak in the BGPS v2.0 maps (Ginsburg et al 2013).…”

Section: New Gbt Nh 3 Observationsmentioning

confidence: 49%

“…HCO 3 2 ( ) (see Shirley et al 2013). Figures 12(b) shows the distributions of observed NH 3 linewidth, indicating a factor of two increase from 1.339±0.014 km s −1 on median toward starless candidates to 2.736±0.03 km s −1 on median toward UCH II associated clumps.…”

Section: Gas Kinetic Temperature and Line Widthmentioning

confidence: 95%

“…Unique radial velocities are determined from observations of dense gas tracers (HCO + , N 2 H + , or NH 3 ; Dunham et al 2011b;Shirley et al 2013) and from morphologically matching the BGPS clumps to the 13 CO spectra from the GRS (see . A Bayesian statistical methodology of formulating clump DPDFs based on a range of prior distributions has been carried out and applied to the BGPS by Ellsworth-Bowers et al (2013,2015).…”

Section: Distance Probability Density Functionsmentioning

confidence: 99%

“…Follow-up spectroscopic observations of the BGPS catalog in dense molecular gas tracers HCO + 3-2 and + N H 2 3-2 with the Arizona Radio Observatory's Heinrich Hertz Submillimeter Telescope (HHSMT; Schlingman et al 2011;Shirley et al 2013) detected about half of the objects in the BGPS catalog (>97% of those clumps have a single velocity component) from which kinematic distances may be derived. A novel Bayesian technique has been developed to calculate a continuous function of the probability that a source lies at a given heliocentric distance (EllsworthBowers et al 2013(EllsworthBowers et al , 2015.…”

Section: Introductionmentioning

confidence: 99%

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The Bolocam Galactic Plane Survey. Xiv. Physical Properties of Massive Starless and Star-Forming Clumps

Svoboda

Shirley

Battersby

et al. 2016

ApJ

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106

200

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We sort 4683 molecular clouds between 10°<ℓ<65°from the Bolocam Galactic Plane Survey based on observational diagnostics of star formation activity: compact 70 μm sources, mid-IR color-selected YSOs, H 2 O and CH 3 OH masers, and UCH IIregions. We also present a combined NH 3 -derived gas kinetic temperature and H 2 O maser catalog for 1788 clumps from our own GBT 100 m observations and from the literature. We identify a subsample of 2223 (47.5%) starless clump candidates (SCCs), the largest and most robust sample identified from a blind survey to date. Distributions of flux density, flux concentration, solid angle, kinetic temperature, column density, radius, and mass show strong (>1 dex) progressions when sorted by star formation indicator. The median SCC is marginally subvirial (α∼0.7) with >75% of clumps with known distance being gravitationally bound (α<2). These samples show a statistically significant increase in the median clump mass of ΔM∼170-370 M e from the starless candidates to clumps associated with protostars. This trend could be due to (i) mass growth of the clumps atM 200 440 -M e Myr −1 for an average freefall 0.8 Myr timescale, (ii) a systematic factor of two increase in dust opacity from starless to protostellar phases, and/or (iii)a variation in the ratio of starless to protostellar clump lifetime that scales as ∼M −0.4 . By comparing to the observed number of CH 3 OH maser containing clumps, we estimate the phaselifetime of massive (M>10 3 M e ) starless clumps to be 0.37±0.08 Myr (M/103 M e ) −1; the majority (M<450 M e ) have phaselifetimes longer than their average freefall time.

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Section: New Gbt Nh 3 Observationsmentioning

confidence: 49%

Section: Gas Kinetic Temperature and Line Widthmentioning

confidence: 95%

Section: Distance Probability Density Functionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Bolocam Galactic Plane Survey. Xiv. Physical Properties of Massive Starless and Star-Forming Clumps

Svoboda

Shirley

Battersby

et al. 2016

ApJ

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106

200

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“…Since the Hi-GAL data convey information only on the continuum emission, we investigated the literature to search for molecular or recombination line observations of the 204 usable targets. In particular, we refer to the following articles: Urquhart et al (2013b; hereafter URQ13), Anderson et al (2009Anderson et al ( , 2012, Beuther et al (2002), Shirley et al (2013), Bronfman et al (1996), Jones et al (2012), Kolpak et al (2003), Pandian et al (2008), Sewilo et al (2004), Watson et al (2003), Wienen et al (2012), and the red MSX source (RMS) database 2 (Lumsden et al 2013). We were able to assign an LSR velocity to all but four (G011.9786-00.0973, G026.0083+00.1369, G026.8304-00.2067, and G065.2462+00.3505) of the 204 sources.…”

Section: Distance Estimatesmentioning

confidence: 99%

Infrared emission of young HII regions: aHerschel/Hi-GAL study

Cesaroni

Pestalozzi

Beltrán

et al. 2015

A&A

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Context. Investigating the relationship between radio and infrared emission of Hii regions may help shed light on the nature of the ionizing stars and the formation mechanism of early-type stars in general. Aims. We have taken advantage of recent unbiased surveys of the Galactic plane such as Herschel/Hi-GAL and VLA/CORNISH to study a bona fide sample of young Hii regions located in the Galactic longitude range 10 • -65 • by comparing the mid-and far-IR continuum emission to the radio free-free emission at 5 GHz. Methods. We have identified the Hi-GAL counterparts of 230 CORNISH Hii regions and reconstructed the spectral energy distributions of 204 of these by complementing the Hi-GAL fluxes with ancillary data at longer and shorter wavelengths. Using literature data, we obtained a kinematical distance estimate for 200 Hii regions with Hi-GAL counterparts and determined their luminosities by integrating the emission of the corresponding spectral energy distributions. We have also estimated the mass of the associated molecular clumps from the (sub)millimeter flux densities. Results. Our main finding is that for ∼1/3 of the Hii regions the Lyman continuum luminosity appears to be greater than the value expected for a zero-age main-sequence star with the same bolometric luminosity. This result indicates that a considerable fraction of young, embedded early-type stars presents a "Lyman excess" possibly due to UV photons emitted from shocked material infalling onto the star itself and/or a circumstellar disk. Finally, by comparing the bolometric and Lyman continuum luminosities with the mass of the associated clump, we derive a star formation efficiency of 5%. Conclusions. The results obtained suggest that accretion may still be present during the early stages of the evolution of Hii regions, with important effects on the production of ionizing photons and thus on the circumstellar environment. More reliable numerical models describing the accretion process onto massive stars are required to shed light on the origin of the observed Lyman excess.

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A Search for High-Mass Stars Forming in Isolation using CORNISH and ATLASGAL

Tremblay

Walsh

Longmore

et al. 2015

Publ. Astron. Soc. Aust.

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Theoretical models of high mass star formation lie between two extreme scenarios. At one extreme, all the mass comes from an initially gravitationally-bound core. At the other extreme, the majority of the mass comes from cluster scale gas, which lies far outside the initial core boundary. One way to unambiguously show high mass stars can assemble their gas through the former route would be to find a high mass star forming in isolation. Making use of recently available CORNISH and ATLASGAL Galactic plane survey data, we develop sample selection criteria to try and find such an object. From an initial list of approximately 200 sources, we identify the high mass star forming region G13.384+0.064 as the most promising candidate. The region contains a strong radio continuum source, that is powered by an early B-type star. The bolometric luminosity, derived from infrared measurements, is consistent with this. However, sub-millimetre continuum emission, measured in ATLASGAL, as well as dense gas tracers, such as HCO + (3-2) and N2H + (3-2) indicate that there is less than ∼ 100 M of material surrounding this star. We conclude that this region is indeed a promising candidate for a high mass star forming in isolation, but that deeper near-IR observations are required to put a stronger constraint on the upper mass limit of young, lower mass stars in the region. Finally, we discuss the challenges facing future studies in proving a given high mass star is forming in isolation.

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THE BOLOCAM GALACTIC PLANE SURVEY. X. A COMPLETE SPECTROSCOPIC CATALOG OF DENSE MOLECULAR GAS OBSERVED TOWARD 1.1 mm DUST CONTINUUM SOURCES WITH 7.°5 ⩽ l ⩽ 194°

Cited by 66 publications

References 61 publications

The Bolocam Galactic Plane Survey. Xiv. Physical Properties of Massive Starless and Star-Forming Clumps

The Bolocam Galactic Plane Survey. Xiv. Physical Properties of Massive Starless and Star-Forming Clumps

Infrared emission of young HII regions: aHerschel/Hi-GAL study

A Search for High-Mass Stars Forming in Isolation using CORNISH and ATLASGAL

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