J/ApJ/710/332 Far-UV sources in M80 (Dieball+, 2010)
A far-ultraviolet survey of M80: X-ray source counterparts, strange blue
stragglers, and the recovery of nova T Sco.
Dieball A., Long K.S., Knigge C., Thomson G.S., Zurek D.R.
<Astrophys. J., 710, 332-345 (2010)>
=2010ApJ...710..332D 2010ApJ...710..332D
ADC_Keywords: Clusters, globular ; Photometry, ultraviolet ;
Cross identifications ; Stars, horizontal branch
Keywords: binaries: close - globular clusters: individual (M80) -
novae, cataclysmic variables - stars: individual (T Scorpii) -
ultraviolet: stars
Abstract:
Using the Advanced Camera for Surveys on Hubble Space Telescope, we
have surveyed the far-ultraviolet (FUV) and near-ultraviolet (NUV)
populations in the core region of M80. The color-magnitude diagram
(CMD) reveals large numbers of blue and extreme horizontal branch
stars and blue stragglers, as well as ∼60 objects lying in the
region of the CMD where accreting and detached white dwarf binaries
are expected. Overall, the blue straggler stars are the most centrally
concentrated population, with their radial distribution suggesting a
typical blue straggler mass of about 1.2M☉. However,
counterintuitively, the faint blue stragglers are significantly more
centrally concentrated than the bright ones and a Kolmogorov-Smirnov
test suggest only a 3.5% probability that both faint and bright blue
stragglers are drawn from the same distribution. This may suggest that
(some) blue stragglers get a kick during their formation. We have also
been able to identify the majority of the known X-ray sources in the
core with FUV bright stars. One of these FUV sources is a likely dwarf
nova that was in eruption at the time of the FUV observations. This
object is located at a position consistent with Nova 1860 AD, or T
Scorpii. Based on its position, X-ray and UV characteristics, this
system is almost certainly the source of the nova explosion. The
radial distribution of the X-ray sources and of the cataclysmic
variable candidates in our sample suggest masses >1M☉.
Description:
The observations of the core of M80 were carried out with the ACS on
board HST using the FUV F165LP filter in the Solar Blind Channel (SBC)
and the NUV F250W filter in the High Resolution Channel (HRC) and were
made at a single pointing position. The FUV observation was carried
out during four consecutive orbits in 2004 September. The NUV
observation (data set j8y504) comprised a single orbit in 2004
October. The FUV and NUV master images are shown in Figures 1 and 2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 128 3168 Catalog of all sources in our FUV field of view
table6.dat 102 48 *Chandra X-ray source comparison
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Note on table6.dat: For some sources, especially those which are faint in
X-rays, and hence have larger error circles, multiple sources lie within the
3σ radius. In these cases, we have listed all of the possible FUV
counterparts in the order of increasing distance from the nominal X-ray
position. The four Chandra sources which were outside the FUV field of view
appear in the table, but only to indicate their improved positions.
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/A+A/417/597 : Radial velocities in 4 globular clusters (Recio-Blanco+, 2004)
J/A+A/391/945 : HST photometry of 74 galactic globular clusters (Piotto+, 2002)
J/ApJ/522/983 : M80 blue straggler stars (Ferraro+, 1999)
J/AJ/116/2415 : CCD UBVRI Photometry of M80 (Alcaino+ 1998)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq [1,3168] Running sequence number
6- 10 I5 --- IDFUV [1,10007] FUV identification number
12- 13 I2 h RAh Hour of Right Ascension (J2000)
15- 16 I2 min RAm Minute of Right Ascension (J2000)
18- 23 F6.3 s RAs Second of Right Ascension (J2000)
25 A1 --- DE- Sign of the Declination (J2000)
26- 27 I2 deg DEd Degree of Declination (J2000)
29- 30 I2 arcmin DEm Arcminute of Declination (J2000)
32- 36 F5.2 arcsec DEs Arcsecond of Declination (J2000)
38- 45 F8.3 pix Xpix FUV image X pixel coordinate
47- 54 F8.3 pix Ypix FUV image Y pixel coordinate
56- 61 F6.3 mag FUV HST/SBC F165LP (far-UV) magnitude (165nm)
63- 67 F5.3 mag e_FUV Error in FUV
69- 74 F6.3 mag NUV ? HST/HRC F250W (near-UV) magnitude (250nm)
76- 80 F5.3 mag e_NUV ? Error in NUV
85- 90 I6 --- IDP [44,200039]? Optical counterpart number (G1)
92- 97 F6.3 mag Bmag ? Johnson B magnitude, reddening corrected
99-104 F6.3 mag Vmag ? Johnson V magnitude, reddening corrected
106-128 A23 --- Comm Additional comments (G2)
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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 A4 --- IDX Chandra source designation (from Heinke et al.,
2003ApJ...598..516H 2003ApJ...598..516H; <[HGE2003] CXNN> in Simbad)
6- 7 I2 h RAh Revised X-ray hour of right ascension (J2000)
9- 10 I2 min RAm Revised X-ray minute of right ascension (J2000)
12- 17 F6.3 s RAs Revised X-ray second of right ascension (J2000)
19 A1 --- DE- Revised X-ray sign of declination (J2000)
20- 21 I2 deg DEd Revised X-ray degree of declination (J2000)
23- 24 I2 arcmin DEm Revised X-ray arcminute of declination (J2000)
26- 30 F5.2 arcsec DEs Revised X-ray arcsecond of declination (J2000)
32- 35 F4.2 arcsec ePos ? 3σ statistical uncertainty
37- 40 F4.2 arcsec Off ? Angular distance from the nominal position
to the FUV object
42- 45 I4 --- IDFUV [214,4850]? FUV source designation (NNNN)
47- 52 F6.3 mag FUV ? HST/SBC FUV band magnitude (F165LP filter)
54- 58 F5.3 mag e_FUV ? FUV uncertainty
60- 65 F6.3 mag NUV ? HST/HRC NUV band magnitude (F250W filter)
67- 71 F5.3 mag e_NUV ? NUV uncertainty
73- 76 I4 --- IDP [923,3338]? Optical counterpart number (G1)
78- 83 F6.3 mag Bmag ? Johnson B magnitude, reddening corrected
85- 90 F6.3 mag Vmag ? Johnson V magnitude, reddening corrected
92-102 A11 --- Comm Additional comments (G2)
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Global notes:
Note (G1): ID number of the optical counterpart taken from Piotto et al. 2002,
Cat. J/A+A/391/945 (<Cl* NGC 6093 PKD NNNNN> in Simbad).
Note (G2): This column includes the source type according to its position
in the FUV-NUV and optical CMD and further comments. Abbreviations used:
BHB = blue horizontal branch stars;
BS = blue stragglers;
EHB = extreme horizontal branch stars;
MS = main sequence stars ;
RG = red giants;
WD = white dwarfs;
AGB = asymptotic giant branch.
HRC = High Resolution Channel (HST/ACS NUV F250W) and
PC = optical data obtained using the WFPC2 F555W in 1996 by Piotto et al.,
2002, Cat. J/A+A/391/945.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 12-Mar-2012