J/AJ/146/162 Wolf-Rayet and RSG stars in M101. I. HST photometry (Shara+, 2013)
The vast population of Wolf-Rayet and red supergiant stars in M101.
I. Motivation and first results.
Shara M.M., Bibby J.L., Zurek D., Crowther P.A., Moffat A.F.J., Drissen L.
<Astron. J., 146, 162 (2013)>
=2013AJ....146..162S 2013AJ....146..162S
ADC_Keywords: Galaxies, nearby ; Photometry, HST ; Stars, supergiant ;
Stars, Wolf-Rayet
Keywords: galaxies: individual: M101 - galaxies: stellar content -
stars: Wolf-Rayet - supergiants
Abstract:
Assembling a catalog of at least 10000 Wolf-Rayet (W-R) stars is an
essential step in proving (or disproving) that these stars are the
progenitors of Type Ib and Type Ic supernovae. To this end, we have
used the Hubble Space Telescope (HST) to carry out a deep, HeII
optical narrowband imaging survey of the ScI spiral galaxy M101.
Almost the entire galaxy was imaged with the unprecedented depth and
resolution that only the HST affords. Differenced with archival
broadband images, the narrowband images allow us to detect much of the
W-R star population of M101. We describe the extent of the survey and
our images, as well as our data reduction procedures. A detailed
broadband-narrowband imaging study of a field east of the center of
M101, containing the giant star-forming region NGC5462, demonstrates
our completeness limits, how we find W-R candidates, their properties
and spatial distribution, and how we rule out most contaminants. We
use the broadband images to locate luminous red supergiant (RSG)
candidates. The spatial distributions of the W-R and RSG stars near
NGC 5462 are strikingly different. W-R stars dominate the complex
core, while RSGs dominate the complex halo. Future papers in this
series will describe and catalog more than a thousand W-R and RSG
candidates that are detectable in our images, as well as spectra of
many of those candidates.
Description:
We used F435W, F555W, and F814W Hubble Space Telescope (HST) Advanced
Camera for Surveys (ACS) images, taken under program ID 9490 (PI:
Kuntz) and ID 10918 (PI: Freedman), to provide continuum images. Thus,
we only needed to acquire the narrowband images with HST/WFC3 and the
F469N filter. The F469N images were taken between 2010 February 25 and
2010 September 27. The archival F435W, F555W, and F814W images were
taken between 2002 November 13 and 2002 November 16. We find the Vega
magnitude system to be more useful, since (under the Vega system) the
F435W, F555W, and F814W filters correspond to the Johnson B, V, and I
filters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 79 75 Photometry of M101 Wolf-Rayet candidates
table2.dat 58 162 HST/ACS photometry of Red SuperGiant (RSG)
candidates in one pointing of M101
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/AJ/146/114 : Massive stars in M101. I. HST BVI photometry (Grammer+, 2013)
J/ApJ/733/124 : Cepheids in M101 observed with HST (Shappee+, 2011)
J/ApJ/508/491 : M101 Cepheids (Stetson+, 1998)
J/ApJ/463/26 : VI photometry of 29 Cepheids in M101. (Kelson+ 1996)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Hour of Right Ascension (J2000) (1)
4- 5 I2 min RAm Minute of Right Ascension (J2000) (1)
7- 12 F6.3 s RAs Second of Right Ascension (J2000) (1)
14 A1 --- DE- Sign of the Declination (J2000) (1)
15- 16 I2 deg DEd Degree of Declination (J2000) (1)
18- 19 I2 arcmin DEm Arcminute of Declination (J2000) (1)
21- 25 F5.2 arcsec DEs Arcsecond of Declination (J2000) (1)
27- 31 F5.2 mag F469N The HST/WFC3 F469N band magnitude
33- 36 F4.2 mag e_F469N Uncertainty in F469N
38- 42 F5.2 mag F435W ? The HST/ACS F435W band VEGA magnitude
44- 47 F4.2 mag e_F435W ? The 1σ uncertainty in F435W
49- 52 F4.2 mag B-469 ? The HST/ACS F435W-F469N color index
54- 57 F4.2 mag e_B-469 ? The 1σ uncertainty in B-469
59- 63 F5.2 mag F555W ? The HST/ACS F555W band VEGA magnitude
65- 68 F4.2 mag e_F555W ? The 1σ uncertainty in F555W
70- 74 F5.2 mag F814W ? The HST/ACS F814W band VEGA magnitude
76- 79 F4.2 mag e_F814W ? The 1σ uncertainty in F814W
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Note (1): The coordinates are taken from the calibration of the F469N/WFC3
images.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Hour of Right Ascension (J2000)
4- 5 I2 min RAm Minute of Right Ascension (J2000)
7- 12 F6.3 s RAs Second of Right Ascension (J2000)
14 A1 --- DE- Sign of the Declination (J2000)
15- 16 I2 deg DEd Degree of Declination (J2000)
18- 19 I2 arcmin DEm Arcminute of Declination (J2000)
21- 25 F5.2 arcsec DEs Arcsecond of Declination (J2000)
27- 31 F5.2 mag F435W The HST/ACS F435W band VEGA magnitude
33- 36 F4.2 mag e_F435W The 1σ uncertainty in F435W
38- 42 F5.2 mag F555W The HST/ACS F555W band VEGA magnitude
44- 47 F4.2 mag e_F555W The 1σ uncertainty in F555W
49- 53 F5.2 mag F814W The HST/ACS F814W band VEGA magnitude
55- 58 F4.2 mag e_F814W The 1σ uncertainty in F814W
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Nomenclature note:
In Tables 1 and 2, stars are <[SBZ2013] JHHMMSS.sss+DDMMSS.ss> in Simbad.
History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 24-Jul-2014