J/AJ/131/866 Hot populations in M87 globular clusters (Sohn+, 2006)
Hot populations in M87 globular clusters.
Sohn S.T., O'Connell R.W., Kundu A., Landsman W.B., Burstein D.,
Bohlin R.C., Frogel J.A., Rose J.A.
<Astron. J., 131, 866-888 (2006)>
=2006AJ....131..866S 2006AJ....131..866S
ADC_Keywords: Galaxies, UV-excess ; Clusters, globular ; Photometry, ultraviolet
Keywords: galaxies: individual (M87) - galaxies: star clusters -
globular clusters: general - ultraviolet: galaxies
Abstract:
To explore the production of UV-bright stars in old, metal-rich
populations like those in elliptical galaxies, we have obtained Hubble
Space Telescope (HST) Space Telescope Imaging Spectrograph far- and
near-UV photometry of globular clusters (GCs) in four fields in the
giant elliptical (gE) galaxy M87. To a limit of mFUV∼25 we detect a
total of 66 GCs in common with the deep HST optical-band study of
Kundu et al. (1999, Cat. J/ApJ/513/733).
Description:
The data used in this study consist of HST STIS (Space Telescope
Imaging Spectrograph) FUV (1270-2000Å, pivot wavelength 1460Å)
and NUV (1480-3500Å, pivot wavelength 2360Å) images of four
different fields in the inner (r<1.5') region of M87. Fields 1, 2, and
3 were observed with the HST STIS far-UV camera in HST program GO-8643
(PI: R. O'Connell). We also obtained three optical band images
centered on the same positions as the far-UV frames of fields 1, 2,
and 3, using the STIS CCD and F28X50LP filter (5500-11000Å, pivot
wavelength 7230Å). Observations of field 4 were taken from the
Space Telescope Science Institute (STScI) HST archive.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 88 22 Photometry of NUV-only sources in Field 4
table4.dat 65 146 Photometric catalog for Field 1, 2, and 3
table5.dat 88 16 Photometric catalog for Field 4
table6.dat 84 31 UV data for Milky Way globular clusters
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See also:
J/ApJ/513/733 : Globular cluster system in M87 (Kundu+, 1999)
J/AJ/106/493 : Globular clusters in M87 (Lee+, 1993)
J/AJ/115/1801 : VRI photometry of M87 globular clusters (Harris+ 1998)
J/ApJS/73/671 : M87 globular clusters BVI photometry (Couture+, 1990)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [NUV-]
5- 6 I2 --- NUV Source identification number
([SOK2006] NUV-NN in Simbad)
8- 13 F6.2 arcsec oRA Offset in Right Ascension (G2)
15- 19 F5.2 arcsec oDE Offset in Declination (G2)
21 A1 --- l_NUVmag1 [>] Limit flag on NUVmag1
22- 27 F6.3 mag NUVmag1 ? Near-UV (2360Å) magnitudes in the STMAG
system at MJD 51315.56
29- 33 F5.3 mag e_NUVmag1 ? Error in NUVmag1 (G3)
35 A1 --- l_NUVmag2 [>] Limit flag on NUVmag2
36- 41 F6.3 mag NUVmag2 ? Near-UV (2360Å) magnitudes in the STMAG
system at MJD 52120.97
43- 47 F5.3 mag e_NUVmag2 ? Error in NUVmag2 (G3)
49 A1 --- l_NUVmag3 [>] Limit flag on NUVmag3
50- 55 F6.3 mag NUVmag3 ? Near-UV (2360Å) magnitudes in the STMAG
system at MJD 52332.20
57- 61 F5.3 mag e_NUVmag3 ? Error in NUVmag3 (G3)
63 A1 --- l_NUVmag4 [>] Limit flag on NUVmag4
64- 69 F6.3 mag NUVmag4 Near-UV (2360Å) magnitudes in the STMAG
system at MJD 52472.37
71- 75 F5.3 mag e_NUVmag4 ? Error in NUVmag4 (G3)
77- 82 F6.3 mag NUVmag Mean Near-UV (2360Å) magnitudes in the
STMAG system
84- 88 F5.3 mag e_NUVmag Error in NUVmag (G3)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- [SOK2006] Source identification number
([SOK2006] NNNN in Simbad) (G1)
6- 10 F5.2 arcsec oRA Right Ascension offset (G2)
12- 17 F6.2 arcsec oDE Declination offset (G2)
19- 23 F5.2 arcsec Dist Angular radial distance from M87 center
25 A1 --- l_FUVmag Limit flag on FUVmag
27- 32 F6.3 mag FUVmag Far-UV (1460Å) magnitude in the STMAG
system
34- 38 F5.3 mag e_FUVmag ? Error in FUVmag (G3) (3)
40 A1 --- l_FUV-V Limit flag on FUV-V
42- 47 F6.3 mag FUV-V Dereddened (FUV-V) color index (G4) (4)
49- 53 F5.3 mag e_FUV-V ? Error in FUV-V
55- 59 F5.3 mag V-I ? Dereddened (V-I) color index (G4) (4)
61- 65 F5.3 mag e_V-I ? Error in V-I
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Note (3): For optical-only sources we determine upper limits to the far-UV
magnitudes using the fluxes plus 3σ when the measured fluxes
are positive and 3σ when the measured fluxes are negative.
Note (4): For UV-only sources, we determine upper limits to the V magnitudes
using the fluxes plus 3σ when the measured fluxes are positive
and 3σ when the measured fluxes are negative.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- [SOK2006] Source identification number
([SOK2006] NNNN in Simbad) (G1) (1)
6- 11 F6.2 arcsec oRA Right Ascension offset (G2)
13- 17 F5.2 arcsec oDE Declination offset (G2)
19- 23 F5.2 arcsec Dist Angular radial distance from M87 center
25- 30 F6.3 mag FUVmag ? Far-UV (1460Å) magnitude in the STMAG
system
32- 36 F5.3 mag e_FUVmag ? Error in FUVmag (G3)
38- 43 F6.3 mag NUVmag Near-UV (2360Å) magnitude in the STMAG
system
45- 49 F5.3 mag e_NUVmag Error in NUVmag (G3)
51- 55 F5.3 mag FUV-V ? Dereddened (FUV-V) color index (G4)
57- 61 F5.3 mag e_FUV-V ? Error in FUV-V
63- 67 F5.3 mag NUV-V Dereddened (NUV-V) color index (G4)
69- 73 F5.3 mag e_NUV-V Error in NUV-V
75- 79 F5.3 mag V-I Dereddened (V-I) color index (G4)
81- 85 F5.3 mag e_V-I Error in V-I
87- 88 I2 --- [KWS99] Kundu et al. (1999, Cat. J/ApJ/513/733)
identification number
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Note (1): This table contains only those Field 4 sources with both UV and
optical identifications. Table 5 contains the UV-only sources in this
field.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- NGC NGC number
6- 16 A11 --- OName Other name
18- 21 F4.2 mag FUV-V ? Dereddened (FUV-V) color index
23- 26 F4.2 mag e_FUV-V ? Error in FUV-V
28- 32 F5.2 mag FUV-NUV ? Dereddened (FUV-NUV) color index
34- 38 F5.2 mag e_FUV-NUV ? Error in FUV-NUV
40- 43 F4.2 mag NUV-V Dereddened (NUV-V) color index
45- 48 F4.2 mag e_NUV-V ? Error in NUV-V
50- 53 F4.2 mag V-I Dereddened (V-I) color index
55- 60 F6.2 mag MV MV Absolute V magnitude
62- 66 F5.2 [Sun] [Fe/H] Abundance [Fe/H]
68- 72 F5.3 mag Mg2 Mg2 line index
74- 78 F5.3 mag e_Mg2 Error in Mg2
80- 83 F4.2 mag E(B-V) (B-V) color excess
84 A1 --- f_E(B-V) [a] Indicates clusters with revised reddenings
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Global Notes:
Note (G1): Each object has a 4 digit ID number. The first digit is the field
number, the second is a flag indicating whether an object meets the
3σ detection criterion both in optical and far-UV (0), only in
optical (1), or only in far-UV (2); and the last two digits are
serial numbers for each detection flag type sorted in order of
ascending oRA.
Note (G2): From the center of M87 at 12 30 49.42 +12 23 28.0 (ICRS; Ma et al.,
1998 Cat. I/251). Note that Kundu et al. (1999, Cat.
J/ApJ/513/733) used different coordinates for the center of M87.
Note (G3): Includes random photon noise, scatter in sky pixel values, and
uncertainties in mean sky measurements.
Note (G4): We used the adopted extinction to correct for reddening. V and I
magnitudes and errors are from a complete catalog of Kundu et al.
(1999, Cat. J/ApJ/513/733).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 12-Jan-2007