Not a galaxy: IRAS 04186+5143, a new young stellar cluster in the outer Galaxy

Yun, J. L.; Elia, D.; Djupvik, A. A.; Torrelles, J. M.; Molinari, S.

doi:10.1093/mnras/stv1431

Cited by 4 publications

(5 citation statements)

References 54 publications

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“…Hereafter we will adopt M env = M. The right panel of the figure clarifies, by means of density contours, how proto-stellar sources are spread in a large area corresponding to a variety of ages, encompassing even evolutionary stages closer to the transition between clump collapse and envelope dissolution (ZAMS). However, since the bolometric luminosities are computed starting from the MIR (∼ 20 µm) or from longer wavelengths, while the most evolved Hi-GAL sources are expected to have also counterparts at shorter wavelengths (e.g., Li et al 2012;Tapia et al 2014;Strafella et al 2015;Yun et al 2015), it is likely that for a fraction of proto-stellar sources the evolutionary stage is underestimated, and the actual spread in age of this population is larger than represented here.…”

Section: Bolometric Luminosity and Temperaturementioning

confidence: 90%

“…Furthermore, one should keep in mind that conditions favourable to the formation of stars might be met only in a fraction of the entire volume of a distant proto-stellar clump. The observed L bol /M ratio of a proto-stellar object is a single observable computed from the global emission of an envelope containing unresolved young stellar objects (YSOs) not necessarily coeval, but more generally at mixed stages of evolution (Yun et al 2015).…”

Section: Bolometric Luminosity and Temperaturementioning

confidence: 99%

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The Hi-GAL compact source catalogue – I. The physical properties of the clumps in the inner Galaxy (−71$_{.}^{\circ}$0 < ℓ < 67$_{.}^{\circ}$0)

Elia

Molinari

Schisano

et al. 2017

Monthly Notices of the Royal Astronomical Society

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158

186

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Hi-GAL is a large-scale survey of the Galactic plane, performed with Herschel in five infrared continuum bands between 70 and 500 µm. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogs presented in Molinari et al. (2016a), covering the portion of Galactic plane −71.0 • < < 67.0 • . The band-merged catalogue contains 100922 sources with a regular SED, 24584 of which show a 70 µm counterpart and are thus considered proto-stellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterise different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in proto-stellar sources compared to prestellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to proto-stellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between "on-arm" and "inter-arm" positions.

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Section: Bolometric Luminosity and Temperaturementioning

confidence: 90%

Section: Bolometric Luminosity and Temperaturementioning

confidence: 99%

The Hi-GAL compact source catalogue – I. The physical properties of the clumps in the inner Galaxy (−71$_{.}^{\circ}$0 < ℓ < 67$_{.}^{\circ}$0)

Elia

Molinari

Schisano

et al. 2017

Monthly Notices of the Royal Astronomical Society

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158

186

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“…Brand & Wouterloot 1994;Snell et al 2002;Yun et al 2015). Among them, we selected 10 molecular clouds identified by Snell et al (2002) because they present a relatively large number of samples and performed systematic studies.…”

Section: Sample Star-forming Regionsmentioning

confidence: 99%

“…In the FOG, the number of reported molecular clouds with associatied star-forming regions has been gradually increasing (e.g. Brand & Wouterloot 1994;Snell et al 2002;Yun et al 2015). Among them, we selected 10 molecular clouds identified by Snell et al (2002) because they present a relatively large number of samples and performed systematic studies.…”

Section: Sample Star-forming Regionsmentioning

confidence: 99%

Star Formation Activity Beyond the Outer Arm. I. WISE-selected Candidate Star-forming Regions

Izumi

Kobayashi

Yasui

et al. 2017

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The outer Galaxy beyond the Outer Arm provides a good opportunity to study star formation in an environment significantly different from that in the solar neighborhood. However, star-forming regions in the outer Galaxy have never been comprehensively studied or cataloged because of the difficulties in detecting them at such large distances. We studied 33 known young star-forming regions associated with 13 molecular clouds at R G ≥ 13.5 kpc in the outer Galaxy with data from the Wide-field Infrared Survey Explorer (WISE) mid-infrared all-sky survey. From their color distribution, we developed a simple identification criterion of star-forming regions in the outer Galaxy with the WISE color. We applied the criterion to all the WISE sources in the molecular clouds in the outer Galaxy at R G ≥ 13.5 kpc detected with the Five College Radio Astronomy Observatory (FCRAO) 12 CO survey of the outer Galaxy, of which the survey region is 102• .41, and successfully identified 711 new candidate star-forming regions in 240 molecular clouds. The large number of samples enables us to perform the statistical study of star-formation properties in the outer Galaxy for the first time. This study is crucial to investigate the fundamental star-formation properties, including star-formation rate, star-formation efficiency, and initial mass function, in a primordial environment such as the early phase of the Galaxy formation.

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“…The mass estimated through the fit represents the real mass for prestellar objects and the envelope mass for protostellar ones (Elia et al 2013). The greybody provides the estimates of T and M, while the bolometric luminosity L bol is estimated as described in Yun et al (2015).…”

Section: The Simulation Of Increased Distancementioning

confidence: 99%

Discussing the distance bias in the estimation of Hi-GAL compact source physical properties – II. Evolutionary status and star formation rate

Baldeschi

Molinari

Elia

et al. 2017

Monthly Notices of the Royal Astronomical Society

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The derivation of the evolutionary stage and rate of star formation of star-forming sites from Galactic single-dish far-infrared and submillimetre surveys suffers from the relatively limited spatial resolution that prevents access to 'core' scales (r ≤ 0.1 pc) for heliocentric distances d 1 kpc. In a previous article, we studied the implications of this 'distance bias' for the mass-radius relationship and its ability to diagnose potential sites for high-mass star formation, using a method that simulates the appearance at large distances of nearby and well-resolved star-forming regions mapped with Herschel. In the present article, we use the same method to quantify the bias introduced in the estimate of the evolutionary stage of dense 'clumps' (r ≥ 0.1 pc) revealed from the Herschel Hi-GAL survey, focusing in particular on the L bol /M env ratio, which is widely used as an evolutionary indicator. Furthermore, we discuss how the star formation rate (SFR) and efficiency (SFE) change with distance. The location of sources extracted from the virtual distance-displaced maps in the L bol versus M env diagram provides evolutionary indications that are consistent with those derived from the underlying population of cores and do not fluctuate substantially with distance. We also show that estimates of the SFR from integrated clump properties are consistent with estimates from the underlying resolved source population and show only minor variations with virtual distance. We conclude that methodologies commonly used to infer evolutionary indicators from clump-integrated quantities from large-scale single-dish Galactic far-infrared and submillimetre surveys are robust against distance and angular-resolution bias.

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Not a galaxy: IRAS 04186+5143, a new young stellar cluster in the outer Galaxy

Cited by 4 publications

References 54 publications

The Hi-GAL compact source catalogue – I. The physical properties of the clumps in the inner Galaxy (−71$_{.}^{\circ}$0 < ℓ < 67$_{.}^{\circ}$0)

The Hi-GAL compact source catalogue – I. The physical properties of the clumps in the inner Galaxy (−71$_{.}^{\circ}$0 < ℓ < 67$_{.}^{\circ}$0)

Star Formation Activity Beyond the Outer Arm. I. WISE-selected Candidate Star-forming Regions

Discussing the distance bias in the estimation of Hi-GAL compact source physical properties – II. Evolutionary status and star formation rate

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