J/AJ/133/44 NGC 346 HST VI photometry (Sabbi+, 2007)
Past and present star formation in the SMC: NGC 346 and its neighborhood.
Sabbi E., Sirianni M., Nota A., Tosi M., Gallagher J., Meixner M.,
Oey M.S., Walterbos R., Pasquali A., Smith L.J., Angeretti L.
<Astron. J., 133, 44-57 (2007)>
=2007AJ....133...44S 2007AJ....133...44S
ADC_Keywords: Magellanic Clouds ; Clusters, open ; Photometry, HST
Keywords: galaxies: star clusters - Magellanic Clouds -
open clusters and associations: individual (NGC 346, BS 90) -
stars: evolution
Abstract:
In the quest to understand how star formation occurs and propagates in
the low-metallicity environment of the Small Magellanic Cloud (SMC),
we acquired deep F555W (∼V) and F814W (∼I) Hubble Space Telescope ACS
images of the young and massive star-forming region NGC 346. These
images and their photometric analysis provide us with a snapshot of
the star formation history of the region. We find evidence for star
formation extending from ∼10Gyr in the past until ∼150Myr in the field
of the SMC. The youngest stellar population (∼3±1Myr) is associated
with the NGC 346 cluster. It includes a rich component of low-mass
pre-main-sequence stars mainly concentrated in a number of subclusters
spatially colocated with CO clumps previously detected by Rubio and
coworkers. Within our analysis uncertainties, these subclusters appear
coeval with each other.
Description:
Multiple images of NGC 346 were obtained in 2004 July using the Wide
Field Channel (WFC) of the Advanced Camera for Surveys (ACS) on board
the Hubble Space Telescope (HST; GO-10248; principal investigator A.
Nota). Several exposures were taken through the filters F555W (V) and
F814W (I).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 63 79960 Photometric catalog of the NGC 346 region
table3.dat 46 16 Main characteristics of the NGC 346 subclusters
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See also:
J/PASP/98/1133 : The open cluster NGC 346 (Niemela+, 1986)
J/AJ/98/1305 : Stellar content of NGC 346 (Massey+, 1989)
J/A+A/436/687 : SMC NGC 346-11 and AV 304 spectra (Hunter+, 2005)
J/ApJS/166/549 : HST/ACS observations of NGC 346 (Gouliermis+, 2006)
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 Running identification number (1)
7- 12 F6.3 mag F555W The F555W filter magnitude
14- 18 F5.3 mag e_F555W The 1σ uncertainty in F555W
20- 25 F6.3 mag F814W The F814W filter magnitude
27- 31 F5.3 mag e_F814W The 1σ uncertainty in F814W
33 I1 h RAh Hour of Right Ascension (J2000)
35- 36 I2 min RAm Minute of Right Ascension (J2000)
38- 43 F6.3 s RAs Second of Right Ascension (J2000)
45 A1 --- DE- Sign of the Declination (J2000)
46- 47 I2 deg DEd Degree of Declination (J2000)
49- 50 I2 arcmin DEm Arcminute of Declination (J2000)
52- 56 F5.2 arcsec DEs Arcsecond of Declination (J2000)
58- 60 A3 --- --- [MPG]
61- 63 I3 --- MPG ? Massey et al. (1989, Cat. J/AJ/98/1305)
identification, Cl* NGC 346 MPG NNN in Simbad
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Note (1): Objects identified as Cl* NGC 346 SSN NNNNN in Simbad
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- [SSN2007] Subcluster designation (Sc NN)
7- 8 I2 h RAh Right ascension (J2000.0)
10- 11 I2 min RAm Right ascension (J2000.0)
13- 16 F4.1 s RAs Right ascension (J2000.0)
18 A1 --- DE- Declination sign (J2000.0)
19- 20 I2 deg DEd Declination (J2000.0)
22- 23 I2 arcmin DEm Declination (J2000.0)
25- 26 I2 arcsec DEs Declination (J2000.0)
28- 30 F3.1 pc Rad Radius of subcluster
32- 33 I2 Myr Age Age of subcluster
35- 37 F3.1 Myr e_Age rms uncertainty on Age
39- 41 I3 --- Npms Total number of pre-main sequence (PMS) stars
43- 46 F4.1 pc-2 Dpms PMS number density (NPMS/pc2)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 15-Nov-2008