J/ApJ/581/258 Infrared photometry in the Arches Cluster (Figer+, 2002)
Massive stars in the Arches Cluster.
Figer D.F., Najarro F., Gilmore D., Morris M., Kim S.S., Serabyn E.,
McLean I.S., Gilbert A.M., Graham J.R., Larkin J.E., Levenson N.A.,
Teplitz H.I.
<Astrophys. J. 581, 258 (2002)>
=2002ApJ...581..258F 2002ApJ...581..258F
ADC_Keywords: Clusters, open ; Stars, emission ; Photometry, infrared
Keywords: Galaxy: center - infrared: stars -
open clusters and associations: individual (Arches) -
stars: early-type - stars: formation - techniques: spectroscopic
Abstract:
We present and use new spectra and narrowband images, along with
previously published broadband images, of stars in the Arches cluster
to extract photometry, astrometry, equivalent width, and velocity
information. The data are interpreted with a wind/atmosphere code to
determine stellar temperatures, luminosities, mass-loss rates, and
abundances. We have doubled the number of known emission-line stars,
and we have also made the first spectroscopic identification of the
main sequence for any population in the Galactic center.
Description:
The HST data were obtained as part of GO-7364 (PI Figer), a program
designed to measure the IMFs in the Arches and Quintuplet clusters
(Figer et al., 1999ApJ...525..750F 1999ApJ...525..750F), determine the star formation
history of the Galactic center (E. Serabyn, D.F. Figer, S.S. Kim,
M. Morris, & R.M. Rich 2002, in preparation), and determine the
nature of the "Pistol star" (Figer et al., 1999ApJ...525..759F 1999ApJ...525..759F).
Broadband images were obtained using HST/NICMOS on UT 1997 September
13/14, in a 2x2 mosaic pattern in the NIC 2 aperture (19.2" on a
side). Four nearby fields, separated from the center of the mosaic
by 59" in a symmetric cross-pattern, were imaged in order to sample
the background population. All fields were imaged in
F110W (λc=1.10µm), F160W (λc=1.60µm),
and F205W (λc=2.05µm).
The narrowband images were obtained at roughly the same time as the
broadband images. One image was obtained in each of the
F187N (λc=1.87µm) and F190N (λc=1.90µm) filters in
the NIC 2 aperture.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 81 196 Massive Stars in Arches Cluster
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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- 3 I3 --- [FNG2002] Identification number (1)
5- 19 A15 --- Desig Designation (2)
21- 26 F6.2 arcsec oRA Right Ascension offset (3)
28- 33 F6.2 arcsec oDE Declination offset (3)
35- 39 F5.2 mag F110W ?=99 The F110W (∼1.10µm) band magnitude
41- 45 F5.2 mag F160W The F160W (∼1.60µm) band magnitude
47- 51 F5.2 mag F205W The F205W (∼2.05µm) band magnitude
53- 56 F4.1 mag KMAG Absolute K band magnitude (4)
58 A1 --- l_Minit Limit flag on Minit
60- 64 F5.1 solMass Minit Initial mass (5)
66- 71 F6.1 0.1nm EW ? The 1.87 micron equivalent width
in Angstroems units (6)
73- 80 E8.2 10mW/m2/nm F190N ? Flux in the F190N band in units of
erg/cm2/s/Angstroems
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Note (1): Assigned by sorting the data in order of increasing KMAG
(decreasing luminosity), and rejecting stars outside the range
1.4<F160Wmag-F205Wmag<2.1.
Note (2): Taken from the following, in order of preference:
Nagata et al. (1995AJ....109.1676N 1995AJ....109.1676N) (Nnn = [NWS95] nn in Simbad),
Cotera et al. (1996ApJ...461..750C 1996ApJ...461..750C) (Cnn = [CEC96] nn in Simbad),
Lang et al. (2001ApJ...551L.143L 2001ApJ...551L.143L) (ARnn = [LGR2001] ARnn in Simbad)
Blum et al. (2001AJ....122.1875B 2001AJ....122.1875B) (Bnn = [BSP2001] nn in Simbad).
Radio sources AR9-17 are newly identified in this paper, and their
coordinates have been extracted from Figure 2 of Lang et al.
(2001ApJ...551L.143).
Note (3): Positions are with respect to 17:45:50.26 -28:49:22:76 (J2000)
and have a relative error of ±0.008".
Note (4): Assumes (F205W-K)0=0, d=8000pc (Reid 1993ARA&A..31..345R 1993ARA&A..31..345R),
(F160W-F205W)0=-0.05 and AK=1.95*E(H-K).
Note (5): Assumes the relation between mass and magnitude for τ=2.5Myr
from the Geneva models with solar metallicity and enhanced mass-loss
rates.
Note (6): Calculated as EW=[(F187N-F190N)/F190N]*ΔλF187N,
where F187N is corrected for extinction and the intrinsic shape of
the spectral energy distribution.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 06-Feb-2003