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J/ApJ/659/1241      Stellar variability in Galactic Center   (Rafelski+, 2007)

Photometric stellar variability in the Galactic Center. Rafelski M., Ghez A.M., Hornstein S.D., Lu J.R., Morris M. <Astrophys. J., 659, 1241-1256 (2007)> =2007ApJ...659.1241R
ADC_Keywords: Stars, variable ; Photometry, infrared Keywords: Galaxy: center - infrared: stars - stars: variables: other Abstract: We report the results of a diffraction-limited, photometric variability study of the central 5"x5" of the Galaxy conducted over the past 10-years using speckle imaging techniques on the W.M. Keck I 10 m telescope. Within our limiting magnitude of mK<16mag for images made from a single night of data, we find a minimum of 15K[2.2um]-band variable stars out of 131 monitored stars. The only periodic source in our sample is the previously identified variable IRS 16SW, for which we measure an orbital period of 19.448±0.002-days. Description: K-band (λ0=2.2um, {DELTA}λ=0.4um) speckle imaging observations of the Galaxy's central stellar cluster were obtained with the W.M. Keck I 10m telescope using the facility near-infrared camera (NIRC). Observations taken from 1995 to 2004 have been described in detail elsewhere (Ghez et al., 1998ApJ...509..678G, 2000Natur.407..349G, 2005ApJ...620..744G; Lu et al., 2005ApJ...625L..51L), and new observations on 2005 April 24-25 were conducted in a similar manner, resulting in diffraction-limited images. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 92 16 List of variable stars table3.dat 92 115 List of nonvariable stars
See also: J/ApJ/523/248 : Variable stars in the Galactic center (Ott+, 1999) J/ApJ/643/1011 : Early-type stars in the center of the Galaxy (Paumard+, 2006) Byte-by-byte Description of file: table[23].dat
Bytes Format Units Label Explanations
1- 10 A10 --- Name Star name (SN-NN = [GKM98] SN-NN in Simbad) 11 A1 --- n_Name [h] least variable (1) 13- 29 A17 --- OName ?=--- Other name (2) 31- 35 F5.2 mag Kmag K magnitude (3) 37- 40 F4.2 mag e_Kmag rms uncertainty on Kmag 42- 45 F4.2 mag var ? Internal variation (table2 only) 47- 50 F4.2 arcsec p Projected distance from Sgr A* (4) 52- 56 F5.2 arcsec DRA Offet in right ascension from Sgr A* (4) 58- 62 F5.2 arcsec DDE Offset in declination from Sgr A* (4) 64- 70 E7.2 --- Prob ? K-S non-variable probability (table2 only) (5) 72- 73 I2 d N Number of nights 75- 86 A12 --- Type ?=--- Stellar spectral type 88- 92 A5 --- Notes Notes (6)
Note (1): h indicates the seven least variable bright stars detected in all images used for scaling of the photometry in order to reduce the fluctuations induced by measurement errors on IRS 16C (see Sect. 3.1). Note (2): Other IDs are from Paumard et al. (2006, Cat. J/ApJ/643/1011, [PGM2006] +x.xx+y.yy, [PGM2006] ENN) and Genzel et al. (2000MNRAS.317..348G, [GEO97] WNN), respectively. Note (3): The magnitudes are Qj corrected using seven bright nonvariable stars, and the uncertainties do not include the 5% absolute calibration uncertainties. Comparison to other sources requires adding them in quadrature. Uncertainties are calculated as the standard deviation of the mean. Note (4): Positions are in arcseconds offset from Sgr A* in 1999.56 Note (5): The K-S probability is equal to 1 for an ideal nonvariable source, and approaches zero for a very variable source Note (6): Notes as follows: a = Identified as nonvariable by Ott et al. (1999, Cat. J/ApJ/523/248). b = Spectroscopic identification by Paumard et al. 2006 (J/ApJ/643/1011). c = Identified as possibly variable by Ott et al. 1999 (J/ApJ/523/248). f = Spectroscopic identification by Ott (2003, Ph.D. thesis, Max-Planck-Institut fur extraterrestrische Physik). We denote sources with clear CO or He lines as early and late, respectively. g = Identification based on the interpretation by Genzel et al. (2003ApJ...594..812G) of m(CO) index of Ott (2003, Ph.D. thesis, Max-Planck-Institut fur extraterrestrische Physik), where Genzel et al. (2003ApJ...594..812G) identify stars with m(CO)≥0.04 as late-type stars and stars with m(CO)0.04 as early-type stars. d = This is our main calibration star and is included in this table only for completeness. e = Spectroscopic identification by Figer et al. (2003ApJ...599.1139F). i = Identified as possibly variable by Ott et al. 1999 (J/ApJ/523/248). j = Spectroscopic identification by Eisenhauer et al.i (2005ApJ...628..246E). k = IRS 16CC appears to be variable in the L band, as discussed in Sect. 3.1.
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 05-Jun-2010
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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