J/ApJ/738/137 HST VI stars in Shapley Constellation III (Gouliermis+, 2011)
Pre-main-sequence stellar populations across Shapley Constellation III.
I. Photometric analysis and identification.
Gouliermis D.A., Dolphin A.E., Robberto M., Gruendl R.A., Chu Y.-H.,
Gennaro M., Henning T., Rosa M., Da Rio N., Brandner W., Romaniello M.,
De Marchi G., Panagia N., Zinnecker H.
<Astrophys. J., 738, 137 (2011)>
=2011ApJ...738..137G 2011ApJ...738..137G
ADC_Keywords: Associations, stellar ; Stars, pre-main sequence ;
Photometry, HST ; Magellanic Clouds
Keywords: Hertzsprung-Russell and C-M diagrams - H II regions -
Magellanic Clouds - stars: formation - stars: pre-main sequence -
open clusters and associations: individual (LH60, LH63, LH72, LH88)
Abstract:
We present our investigation of pre-main-sequence (PMS) stellar
populations in the Large Magellanic Cloud (LMC) from imaging with
Hubble Space Telescope Wide-Field Planetary Camera 2. Our targets of
interest are four star-forming regions located at the periphery of the
super-giant shell LMC 4 (Shapley Constellation III). The PMS stellar
content of the regions is revealed through the differential Hess
diagrams and the observed color-magnitude diagrams (CMDs). Further
statistical analysis of stellar distributions along cross sections of
the faint part of the CMDs allowed the quantitative assessment of the
PMS stars census, and the isolation of faint PMS stars as the true
low-mass stellar members of the regions. These distributions are found
to be well represented by a double-Gaussian function, the first
component of which represents the main-sequence field stars and the
second the native PMS stars of each region. Based on this result, a
cluster membership probability was assigned to each PMS star according
to its CMD position. The higher extinction in the region LH 88 did not
allow the unambiguous identification of its native stellar population.
The CMD distributions of the PMS stars with the highest membership
probability in the regions LH 60, LH 63, and LH 72 exhibit an
extraordinary similarity among the regions, suggesting that these
stars share common characteristics, as well as common recent star
formation history. Considering that the regions are located at
different areas of the edge of LMC 4, this finding suggests that star
formation along the super-giant shell may have occurred almost
simultaneously.
Description:
Our investigation is based on the analysis of data collected within
our HST program GO-11547 (PI: D. Gouliermis) that imaged young stellar
clusters located at the apparent edge of the super-giant shell LMC 4.
Our targets are the young associations LH 60, LH 63, LH 72, and LH 88
(Lucke & Hodge 1970AJ.....75..171L 1970AJ.....75..171L). The first pointing was centered
on the brightest part of the associated HII region and WFPC2 imaging
was performed in the broadband filters F300W, F450W, F555W, F814W, and
the narrowband filter F656N, roughly equivalent to standard U, B, V,
I, and Hα, respectively. LH 63 was observed in 2008 Jul 15 and
19; LH 60 in 2008 Jul 18 and 19; LH 72 in 2008 Jul 21 and 14 and LH 88
in 2008 Sep 1 and Jul 9.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 117 44649 The multi-band photometric catalog of stars primarily
detected in both F555W and F814W filters
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
II/236 : UBVR CCD survey of the Magellanic clouds (Massey+, 2002)
J/A+A/542/A66 : YSOs in 9 LMC star forming regions (Carlson+, 2012)
J/ApJS/184/172 : High- and intermediate-mass YSOs in the LMC (Gruendl+, 2009)
J/AJ/133/44 : NGC 346 HST VI photometry (Sabbi+, 2007)
J/AJ/116/1275 : UBV photometry in 5 fields of the LMC (Dolphin+, 1998)
J/ApJS/91/583 : MC massive stars IMF. I. (Hill+, 1994)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- --- [LH]
4- 5 I2 --- LH Star forming region number (60, 63, 72 or 88)
7- 11 I5 --- Seq [1/12511] Stellar index number (1)
13- 22 F10.7 deg RAdeg [81.7/84.1] Right Ascension (J2000)
24- 34 F11.7 deg DEdeg [-67.7/-66.4] Declination (J2000)
36- 43 F8.2 pix Xpix X pixel coordinate
45- 52 F8.2 pix Ypix Y pixel coordinate
54- 59 F6.3 mag F300W ?=99.999 HST/WFPC2 F300W band magnitude (2)
61- 65 F5.3 mag e_F300W ?=9.999 Uncertainty in F300W (2)
67- 72 F6.3 mag F450W ?=99.999 HST/WFPC2 F450W band magnitude (2)
74- 78 F5.3 mag e_F450W ?=9.999 Uncertainty in F450W (2)
80- 85 F6.3 mag F555W [17.732/26.777] HST/WFPC2 F555W band magnitude
87- 91 F5.3 mag e_F555W Uncertainty in F555W
93- 98 F6.3 mag F814W [16.732/25.623] HST/WFPC2 F814W band magnitude
100-104 F5.3 mag e_F814W Uncertainty in F814W
106-111 F6.3 mag F656N ?=99.999 HST/WFPC2 F656N band magnitude (2)
113-117 F5.3 mag e_F656N ?=9.999 Uncertainty in F656N (2)
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Note (1): 12511 stars in LH 60, 11785 in LH 63, 9756 in LH 72, and 10597 in
LH 88 detected in both F555W and F814W filters.
Note (2): A '99.999±9.999' value correspond to non-detection of the
source in the specific filter.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 23-Jan-2013