First GLIMPSE Results on the Stellar Structure of the Galaxy

Benjamin, Robert A.; Churchwell, E.; Babler, B.; Indebetouw, R.; Meade, M. R.; Whitney, B. A.; Watson, C.; Wolfire, M. G.; Wolff, Michael; Ignace, R.; Bania, T. M.; Bracker, S.; Clemens, D. P.; Chomiuk, Laura; Cohen, Martin; Dickey, John M.; Jackson, James M.; Kobulnicky, Henry A.; Mercer, E. P.; Mathis, J. S.; Stolovy, S.; Uzpen, B.

doi:10.1086/491785

Cited by 381 publications

(448 citation statements)

References 13 publications

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“…There are, however, larger numbers of candidate SNRs near 30 • compared with the G14 population. The long bar ends at 30 • (Benjamin et al, 2005), and the giant H II region W43 is at this longitude. There is also a greater number of star formation regions at 30 • , as seen in the WISE H II region distribution in Figs.…”

Section: Comparison With Known Snrs and Hii Regionsmentioning

confidence: 95%

Galactic supernova remnant candidates discovered by THOR

Anderson

Wang

Bihr

et al. 2017

A&A

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141

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Context. There is a considerable deficiency in the number of known supernova remnants (SNRs) in the Galaxy compared to that expected. This deficiency is thought to be caused by a lack of sensitive radio continuum data. Searches for extended low-surface brightness radio sources may find new Galactic SNRs, but confusion with the much larger population of H II regions makes identifying such features challenging. SNRs can, however, be separated from H II regions using their significantly lower mid-infrared (MIR) to radio continuum intensity ratios. Aims. Our goal is to find missing SNR candidates in the Galactic disk by locating extended radio continuum sources that lack MIR counterparts. Methods. We use the combination of high-resolution 1-2 GHz continuum data from The HI, OH, Recombination line survey of the Milky Way (THOR) and lower-resolution VLA 1.4 GHz Galactic Plane Survey (VGPS) continuum data, together with MIR data from the Spitzer GLIMPSE, Spitzer MIPSGAL, and WISE surveys to identify SNR candidates. To ensure that the candidates are not being confused with H II regions, we exclude radio continuum sources from the WISE Catalog of Galactic H II Regions, which contains all known and candidate H II regions in the Galaxy. Results. We locate 76 new Galactic SNR candidates in the THOR and VGPS combined survey area of 67.4 • > > 17.5 • , | b | ≤ 1.25 • and measure the radio flux density for 52 previously-known SNRs. The candidate SNRs have a similar spatial distribution to the known SNRs, although we note a large number of new candidates near 30 • , the tangent point of the Scutum spiral arm. The candidates are on average smaller in angle compared to the known regions, 6.4 ± 4.7 versus 11.0 ± 7.8 , and have lower integrated flux densities.Conclusions. The THOR survey shows that sensitive radio continuum data can discover a large number of SNR candidates, and that these candidates can be efficiently identified using the combination of radio and MIR data. If the 76 candidates are confirmed as true SNRs, for example using radio polarization measurements or by deriving radio spectral indices, this would more than double the number of known Galactic SNRs in the survey area. This large increase would still, however, leave a discrepancy between the known and expected SNR populations of about a factor of two.

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Section: Comparison With Known Snrs and Hii Regionsmentioning

confidence: 95%

Galactic supernova remnant candidates discovered by THOR

Anderson

Wang

Bihr

et al. 2017

A&A

Self Cite

141

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“…The availability of large photometric and spectroscopic datasets from ongoing surveys are finally allowing us to obtain a wider view of the length. The position angle of the bar has been historically measured to range between ∼20−40 deg with respect to the Suncentre line of sight with its near end towards positive Galactic longitudes (Blitz & Spergel 1991;Stanek et al 1994;Dwek et al 1995;Binney et al 1997;Bissantz & Gerhard 2002;Benjamin et al 2005;Babusiaux & Gilmore 2005;Rattenbury et al 2007;Cao et al 2013). Recently, detailed comparisons of RC stellar counts to N-body models (e.g.…”

Section: Introductionmentioning

confidence: 99%

The GIRAFFE Inner Bulge Survey (GIBS)

Gonzalez

Zoccali

Vásquez

et al. 2015

A&A

126

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Aims. We investigate metallicity and α-element abundance gradients along a Galactic longitude strip, at latitude b ∼ −4 • , with the aim of providing observational constraints for the structure and origin of the Milky Way bulge. Methods. High-resolution (R ∼ 22 500) spectra for 400 K giants, in four fields within −4. This knee is in agreement with our previous bulge study of K-giants along the minor axis, but is 0.1 dex lower in metallicity than the value reported for the microlensed dwarf and subgiant stars in the bulge. We found no variation in α-element abundance distributions between different fields.

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“…This region is very luminous with L ∼ 3 × 10 6 L , and it contains sources at different evolutionary stages from a Wolf-Rayet cluster to active young star-forming cores (e.g., Blum et al 1999;Motte et al 2003). Nguyen Luong et al (2011) recently discussed several broad velocity components in that regions and suggested that this whole complex might have formed via converging gas flows due to its special location at the interface of the Galactic bar with the inner Scutum spiral arm (Benjamin et al 2005;López-Corredoira et al 2007;Rodriguez-Fernandez & Combes 2008). Different velocity components were also identified in atomic HI emission and absorption (Liszt et al 1993).…”

Section: Introductionmentioning

confidence: 99%

The onset of high-mass star formation in the direct vicinity of the Galactic mini-starburst W43

Beuther

Tackenberg

Linz

et al. 2012

A&A

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Context. The earliest stages of high-mass star formation are still poorly characterized. Densities, temperatures and kinematics are crucial parameters for simulations of high-mass star formation. It is also unknown whether the initial conditions vary with environment. Aims. We want to investigate the youngest massive gas clumps in the environment of extremely active star formation. Methods. We selected the IRDC 18454 complex, directly associated with the W43 Galactic mini-starburst, and observed it in the continuum emission between 70 μm and 1.2 mm with Herschel, APEX and the 30 m telescope, and in spectral line emission of N 2 H + and 13 CO with the Nobeyama 45 m, the IRAM 30 m and the Plateau de Bute Interferometer. Results. The multi-wavelength continuum study allows us to identify clumps that are infrared dark even at 70 μm and hence the best candidates to be genuine high-mass starless gas clumps. The spectral energy distributions reveal elevated temperatures and luminosities compared to more quiescent environments. Furthermore, we identify a temperature gradient from the W43 mini-starburst toward the starless clumps. We discuss whether the radiation impact of the nearby mini-starburst changes the fragmentation properties of the gas clumps and by that maybe favors more high-mass star formation in such an environment. The spectral line data reveal two different velocity components of the gas at 100 and 50 km s −1 . While chance projection is a possibility to explain these components, the projected associations of the emission sources as well as the prominent location at the Galactic bar -spiral arm interface also allow the possibility that these two components may be spatially associated and even interacting. Conclusions. High-mass starless gas clumps can exist in the close environment of very active star formation without being destroyed. The impact of the active star formation sites may even allow for more high-mass stars to form in these 2nd generation gas clumps. This particular region near the Galactic bar -spiral arm interface has a broad distribution of gas velocities, and cloud interactions may be possible.

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First GLIMPSE Results on the Stellar Structure of the Galaxy

Cited by 381 publications

References 13 publications

Galactic supernova remnant candidates discovered by THOR

Galactic supernova remnant candidates discovered by THOR

The GIRAFFE Inner Bulge Survey (GIBS)

The onset of high-mass star formation in the direct vicinity of the Galactic mini-starburst W43

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