J/AJ/139/1413 M81 star cluster candidates (Nantais+, 2010)
Star cluster candidates in M81.
Nantais J.B., Huchra J.P., McLeod B., Strader J., Brodie J.P.
<Astron. J., 139, 1413-1425 (2010)>
=2010AJ....139.1413N 2010AJ....139.1413N
ADC_Keywords: Galaxies, nearby ; Associations, stellar ; Photometry
Keywords: galaxies: individual (M81) - galaxies: spiral -
galaxies: star clusters: general - galaxies: stellar content
Abstract:
We present a catalog of extended objects in the vicinity of M81 based
on a set of 24 Hubble Space Telescope Advanced Camera for Surveys Wide
Field Camera F814W (I-band) images. We have found 233 good globular
cluster (GC) candidates; 92 candidate HII regions, OB associations,
or diffuse open clusters; 489 probable background galaxies; and 1719
unclassified objects. We have color data from ground-based g- and
r-band MMT Megacam images for 79 galaxies, 125 GC candidates, 7 HII
regions, and 184 unclassified objects. The color-color diagram of GC
candidates shows that most fall into the range 0.25<g-r<1.25 and
0.5<r-I<1.25, similar to the color range of Milky Way GCs.
Unclassified objects are often blue, suggesting that many of them are
likely to be HII regions and open clusters, although a few galaxies
and GCs may be among them.
Description:
Our primary data are a set of 24 HST ACS Wide Field Camera (WFC) F814W
(I-band) images taken between 2004 September 16 and 2005 September 7,
most with total exposures of 1650s, from HST Proposal No. 10250. In
addition, we have also obtained MMT Megacam g and r images of M81
taken 2006 June 5, with 900s exposure time each.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 84 2533 Object list
table2.dat 83 2533 Photometry of extended objects
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See also:
J/AJ/109/1055 : Globulars of M81 (Perelmuter+ 1995)
J/ApJ/438/181 : Observations of H II Regions in M81 (Hill+ 1995)
J/AJ/122/1330 : HST BVI photometry of M 81 star clusters (Chandar+, 2001)
J/MNRAS/405/1293 : Compact star clusters in M81 (Santiago-Cortes+, 2010)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ID [1/2533] Running index identification number,
<[NHM2010] NNNN> in Simbad
6- 7 I2 h RAh Hour of Right Ascension (J2000)
9- 10 I2 min RAm Minute of Right Ascension (J2000)
12- 16 F5.2 s RAs Second of Right Ascension (J2000)
18 A1 --- DE- Sign of Declination (J2000)
19- 20 I2 deg DEd Degree of Declination (J2000)
22- 23 I2 arcmin DEm Arcminute of Declination (J2000)
25- 29 F5.2 arcsec DEs Arcsecond of Declination (J2000)
31- 34 F4.2 arcsec FWHM Full-Width at Half-Maximum
36- 39 F4.2 --- Elong [1/6] Elongation (b/a)
41- 45 I5 --- PR ? Closest Perelmuter and Racine
(1995, Cat. J/AJ/109/1055) object
46 A1 --- u_PR [?] Uncertainty flag on PR
48- 50 I3 --- CFT ? Closest Chandar, Ford, and Tsvetanov
(2001, Cat. J/AJ/122/1330) object
51- 53 A3 --- n_CFT [(b) ] Note on CFT (unexplained)
55- 67 A13 --- Spec Spectroscopic match (1)
69- 79 A11 --- Type Source type: GC cand, Galaxy, Galaxy+Star,
HII/OB or Other
81- 84 F4.2 arcsec Off ? Megacam offset
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Note (1): From Perelmuter, Brodie, and Huchra (1995AJ....110..620P 1995AJ....110..620P) for IDs
with 5 digits (<[PR95] NNNNN>), or Schroder et al. (2002AJ....123.2473S 2002AJ....123.2473S)
if preceded by SBKHP ().
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ID [1/2533] Running index identification number,
<[NHM2010] NNNN> in Simbad
6- 11 F6.3 mag Imag ? I band magnitude
13- 17 F5.3 mag e_Imag ? The 1σ error in Imag
19- 24 F6.3 mag r-I ? The (r-I) color index
26- 30 F5.3 mag e_r-I ? The 1σ error in r-I
32- 37 F6.3 mag g-r ? The (g-r) color index
39- 43 F5.3 mag e_g-r ? The 1σ error in g-r
45- 48 F4.2 arcsec Rad ? HST radius
50- 58 A9 --- Note HST sky annulus note (2)
60- 63 F4.2 arcsec SkyIn ? Inner boundary of sky annulus for colors (2)
65- 68 F4.2 arcsec SkyWid ? Width of sky annulus for colors (2)
70- 83 A14 --- Color Color note (3)
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Note (2): annuli are used for the determination of the sky background.
If the HST sky annulus is different from the standard size chosen for
the photometry radius, then the inner radius and width of the sky annulus
are provided in the "Note" column, in pixels (1 pixel=0.05").
See details in section 3 of the paper.
Note (3): The flag "m.edge" denotes an object within 10 pixels of the edge of a
Megacam image; ap=(number in arcseconds) represents a smaller aperture used
for colors in the cases of blended or edge objects; "m.cut" represents an
object cut off in the Megacam image; and "h.edge" refers to an object near
the edge of an HST image for which the sky annulus and possibly the object
are affected.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 21-May-2012