J/ApJ/864/71 Fluxes & physical param. of blended YSOs (Martinez-Galarza+, 2018)
Unraveling the spectral energy distributions of clustered YSOs.
Martinez-Galarza J.R., Protopapas P., Smith H.A., Morales E.F.E.
<Astrophys. J., 864, 71 (2018)>
=2018ApJ...864...71M 2018ApJ...864...71M
ADC_Keywords: YSOs; Photometry, infrared; Stars, ages; Stars, masses;
Stars, distances; Extinction; Galactic plane
Keywords: methods: statistical ; open clusters and associations: general ;
stars: formation ; stars: protostars ; stars: statistics
Abstract:
Despite significant evidence suggesting that intermediate- and
high-mass stars form in clustered environments, how stars form when
the available resources are shared is still not well understood. A
related question is whether the initial mass function (IMF) is in fact
universal across galactic environments, or whether it is an average of
IMFs that differ, for example, in massive versus low-mass molecular
clouds. One of the long-standing problems in resolving these questions
and in the study of young clusters is observational: how to accurately
combine multiwavelength data sets obtained using telescopes with
different spatial resolutions. The resulting confusion hinders our
ability to fully characterize clustered star formation. Here we
present a new method that uses Bayesian inference to fit the blended
spectral energy distributions and images of individual young stellar
objects (YSOs) in confused clusters. We apply this method to the
infrared photometry of a sample comprising 70 Spitzer-selected,
low-mass (Mcl<100M☉) young clusters in the galactic plane, and
we use the derived physical parameters to investigate how the
distribution of YSO masses within each cluster relates to the total
mass of the cluster. We find that for low-mass clusters this
distribution is indistinguishable from a randomly sampled Kroupa IMF
for this range of cluster masses. Therefore, any effects of
self-regulated star formation that affect the IMF sampling are likely
to play a role only at larger cluster masses. Our results are also
compatible with smoothed particle hydrodynamics models that predict a
dynamical termination of the accretion in protostars, with massive
stars undergoing this stopping at later times in their evolution.
Description:
We use observations from the GLIMPSE (Benjamin+ 2003PASP..115..953B 2003PASP..115..953B &
Churchwell+ 2009PASP..121..213C 2009PASP..121..213C) and MIPS Inner Galactic Plane Survey
(MIPSGAL; Carey+ 2005AAS...207.6333C 2005AAS...207.6333C) surveys, carried out with the
Spitzer Space Telescope's InfraRed Array Camera (IRAC) using bands
IRAC 1 (3.6um), IRAC 2 (4.5um), IRAC 3 (5.6um), and IRAC 4 (8.0um).
The data set of observations studied here covers the inner Galactic
plane (|l|<65°).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 133 218 GLIMPSE sources, derived fluxes and physical parameters
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See also:
II/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)
VIII/96 : 6-GHz methanol multibeam maser catalogue (Caswell+, 2010-12)
J/A+A/434/613 : Water maser survey of methanol masers (Szymczak+, 2005)
J/ApJ/669/327 : S3MC: YSOs in N66, in SMC (Simon+, 2007)
J/AJ/136/2413 : Galactic midplane Spitzer red sources (Robitaille+, 2008)
J/A+A/525/A149 : Red MSX Survey (RMS): bol. fluxes of YSOs (Mottram+, 2011)
J/A+A/542/A66 : YSOs in 9 LMC star forming regions (Carlson+, 2012)
J/A+A/560/A76 : Stellar clusters in the inner Galaxy (Morales+, 2013)
J/MNRAS/431/1752 : ATLASGAL 6.7GHz methanol masers (Urquhart+, 2013)
J/ApJ/778/96 : Spitzer and NEWFIRM observations of NGC 6334 (Willis+, 2013)
J/AJ/149/64 : MIPSGAL 24µm point source catalog (Gutermuth+, 2015)
J/AJ/150/95 : Masses and ages of YSOs in Per OB2 (Azimlu+, 2015)
J/ApJ/815/130 : High-mass molecular clumps from MALT90 (Guzman+, 2015)
J/A+A/579/A91 : ATLASGAL inner Gal. massive cold dust clumps (Wienen+, 2015)
J/ApJ/818/73 : Protostars in Perseus molecular cloud (Tobin+, 2016)
J/A+A/599/A14 : Taurus ultra-wide pairs (Joncour+, 2017)
J/ApJ/839/113 : Mol. clouds with GLIMPSE/MIPSGAL data (Retes-Romero+, 2017)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- ID [360/18738] Source identifier
7- 14 F8.4 deg RAdeg [265.7/297] Right ascension (J2000)
16- 23 F8.4 deg DEdeg [-30.6/25.3] Declination (J2000)
25 A1 --- l_Dist Limit flag on Dist
26- 30 F5.2 kpc Dist [0.5/14] Distance
32- 35 F4.2 kpc e_Dist [0.09/2.1] Distance uncertainty δd
37- 42 F6.2 mJy F3.6 [0.01/117]?=0 Spitzer/IRAC 3.6um flux
44- 47 F4.2 mJy e_F3.6 [0.01/9]?=0 F3.6 uncertainty
49- 54 F6.2 mJy F4.5 [0.01/333]?=0 Spitzer/IRAC 4.5um flux
56- 60 F5.2 mJy e_F4.5 [0.01/26]?=0 F4.5 uncertainty
62- 67 F6.2 mJy F5.8 [0.01/583]?=0 Spitzer/IRAC 5.8um flux
69- 73 F5.2 mJy e_F5.8 [0.01/37]?=0 F5.8 uncertainty
75- 80 F6.2 mJy F8.0 [0.01/583]?=0 Spitzer/IRAC 8.0um flux
82- 86 F5.2 mJy e_F8.0 [0.01/37]?=0 F8.0 uncertainty
88- 91 F4.2 [yr] logt* [0.06/7] Age
93- 96 F4.2 [yr] e_logt* [0/2]? Negative uncertainty on logt*
98-101 F4.2 [yr] E_logt* [0/1.7]? Positive uncertainty on logt*
103-107 F5.2 [Msun] logM* [-1/1.4]? Stellar mass
109-112 F4.2 [Msun] e_logM* [0/0.7]? Negative uncertainty on logM*
114-117 F4.2 [Msun] E_logM* [0/1.4]? Positive uncertainty on logM*
119-123 F5.2 mag logAv [-1.4/1.9]? Visual extinction
125-128 F4.2 mag e_logAv [0/0.8]? Negative uncertainty on logAv
130-133 F4.2 mag E_logAv [0/0.8]? Positive uncertainty on logAv
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 16-Aug-2019