A Catalog of Extended Green Objects in the Glimpse Survey: A New Sample of Massive Young Stellar Object Outflow Candidates

Cyganowski, C. J.; Whitney, B. A.; Holden, Edward S.; Braden, Ella K.; Brogan, C. L.; Churchwell, E.; Indebetouw, R.; Watson, Dorothy; Babler, B.; Benjamin, Robert A.; Gómez, Mercedes; Meade, M. R.; Povich, Matthew S.; Robitaille, Thomas; Watson, C.

doi:10.1088/0004-6256/136/6/2391

Cited by 429 publications

(786 citation statements)

References 38 publications

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“…The UCHII complex is remarked with a circle. Also, the EGO discovered by Cyganowski et al (2008) is indicated. The angular resolutions are ∼1.…”

Section: Resultsmentioning

confidence: 99%

The environs of the ultracompact HII region G45.45+0.06

Paron¹,

Cichowolski²,

Ortega³

2009

A&A

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Aims. G45.45+0.06 is an ultra-compact HII (UCHII) region that has been extensively studied. It is known that G45.45+0.06 is embedded in a complex of UCHII regions, but to date, the surrounding ISM on a larger spatial scale has not been analyzed. Methods. Using data from large-scale surveys, the Two Micron All Sky Survey, GLIMPSE, MIPSGAL, MAGPIS and GRS, we performed a multiwavelength study of a region of about 7 × 7 in the vicinity of G45.45+0.06. Results. We found that the UCHII complex lies on the border of a larger (diameter of ∼3 ) and fainter HII region, which is located at the same distance as G45.45+0.06, ∼8 kpc. In this work, this larger HII region is called G45L. A good morphological correlation is observed between the PDRs and the molecular gas mapped in the 13 CO J = 1−0 and CS J = 2−1 lines, suggesting that G45L may be collecting molecular material. From a near-and mid-IR photometric study, we found three sources, likely O-type stars, that are possibly responsible for the creation of G45L. Additionally, we found several YSO candidates lying preferentially in the molecular shell that surrounds G45L. Our results confirm that the region southeast of the UCHII complex where G45.45+0.06 is embedded and east of G45L is undergoing active star formation. We suggest that G45L has been expanding for about 2 × 10 6 yr and could have triggered the formation of the zero-age main sequence stars that ionize the UCHII region G45.45+0.06. However we cannot discard that both HII regions are coeval.

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“…The UCHII complex is remarked with a circle. Also, the EGO discovered by Cyganowski et al (2008) is indicated. The angular resolutions are ∼1.…”

Section: Resultsmentioning

confidence: 99%

The environs of the ultracompact HII region G45.45+0.06

Paron¹,

Cichowolski²,

Ortega³

2009

A&A

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“…The most luminous of this group is CXO J181854.64-164749.1, discussed in Section 5.5. This source is associated with protostellar outflow activity, traced by a MIR "EGO" source (Cyganowski et al 2008) and a water maser (Sato et al 2010) in a foreground cluster on the corner of our ACIS FOV. We will present a detailed study of the X-ray spectra of these and other remarkable sources associated with high-mass stars, protostars, or IMPS in a subsequent paper.…”

Section: Science Discoveriesmentioning

confidence: 94%

RAPID CIRCUMSTELLAR DISK EVOLUTION AND AN ACCELERATING STAR FORMATION RATE IN THE INFRARED DARK CLOUD M17 SWex

Povich

Townsley

Robitaille

et al. 2016

ApJ

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We present a catalog of 840 X-ray sources and first results from a 100 ks Chandra X-ray Observatory imaging study of the filamentary infrared (IR) dark cloud G014.225-00.506, which forms the central regions of a larger cloud complex known as the M17 southwest extension (M17 SWex). In addition to the rich population of protostars and young stellar objects with dusty circumstellar disks revealed by archival data from the Spitzer Space Telescope, we discover a population of X-ray-emitting, intermediate-mass pre-main-sequence stars that lack IR excess emission from circumstellar disks. We model the IR spectral energy distributions of this source population to measure its mass function and place new constraints on the destruction timescales for the inner dust disk for 2-8 M ☉ stars. We also place a lower limit on the star formation rate (SFR) and find that it is quite high (  M 0.007 M ☉ yr −1 ), equivalent to several Orion Nebula Clusters in G14.225-0.506 alone, and likely accelerating. The cloud complex has not produced a population of massive, O-type stars commensurate with its SFR. This absence of very massive (20 M ☉ ) stars suggests that either (1) M17 SWex is an example of a distributed mode of star formation that will produce a large OB association dominated by intermediate-mass stars but relatively few massive clusters, or (2) the massive cores are still in the process of accreting sufficient mass to form massive clusters hosting O stars.

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“…The presence of an IRDC is an important signpost that the selected objects are indeed sites of massive star formation. The star formation activity in VVVv374 is further evident through the presence of an extremely green object (EGO; Cyganowski et al 2008). The right panel in Figure 1 shows this feature for VVVv374, highlighting the bipolar outflow traced by the EGO.…”

Section: High-amplitude Variable Stars Within Atlasgal Clumpsmentioning

confidence: 99%

Highly Variable Young Massive Stars in Atlasgal Clumps

Kumar

Peña

Lucas

2016

ApJ

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High-amplitude variability in young stellar objects (YSOs) is usually associated with episodic accretion events. It has not been observed so far in massive YSOs. Here, the high-amplitude variable star sample of Contreras Peña et al. has been used to search for highly variable (ΔK 1 mag) sources coinciding with dense clumps mapped using the 850μm continuum emission by the ATLASGAL survey. A total of 18 variable sources are centered on the submillimeter clump peaks and coincide (<1″) with a 24μm point or compact (<10″) source. Of these 18 sources, 13 can be fit by YSO models. The 13 variable YSOs (VYSOs) have luminosities of ∼10 3 L e , an average mass of 8M e , and a range of ages up to 10 6 yr. A total of 11 of these 13 VYSOs are located in the midst of infrared dark clouds. Nine of the 13 sources have ΔK>2 mag, significantly higher compared to the mean variability of the entire VVV sample. The light curves of these objects sampled between 2010 and 2015 display rising, declining, or quasi-periodic behavior but no clear periodicity. Light-curve analysis using the Plavchan method shows that the most prominent phased signals have periods of a few hundred days. The nature and timescale of variations found in 6.7 Ghz methanol maser emission in massive stars are similar to that of the VYSO light curves. We argue that the origin of the observed variability is episodic accretion. We suggest that the timescale of a few hundred days may represent the frequency at which a spiraling disk feeds dense gas to the young massive star.

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A Catalog of Extended Green Objects in the Glimpse Survey: A New Sample of Massive Young Stellar Object Outflow Candidates

Cited by 429 publications

References 38 publications

The environs of the ultracompact HII region G45.45+0.06

The environs of the ultracompact HII region G45.45+0.06

RAPID CIRCUMSTELLAR DISK EVOLUTION AND AN ACCELERATING STAR FORMATION RATE IN THE INFRARED DARK CLOUD M17 SWex

Highly Variable Young Massive Stars in Atlasgal Clumps

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