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Detailed Description of II/295 :
Spitzer IRAC survey of the galactic center (Ramirez+, 2008)

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Note : this is the description file of the original catalog. This HTML page corresponds well to the original description, but some minor changes in the format may have been introduced in the FITS output files in order to allow for arithmetic operations on quantities such as coordinates and times. h:m:s and d:m:s units are normally converted into degrees, and YYYY-MM-DD into julian days.
Similarly, some slight changes may have been introduced in the units; the value given in the HTML files supersedes the value indicated in the ReadMe file for this catalogue.
II/295           Spitzer IRAC survey of the galactic center     (Ramirez+, 2008)
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Point sources from a Spitzer IRAC survey of the galactic center.
    Ramirez S.V., Arendt R.G., Sellgren K., Stolovy S.R., Cotera A.,
    Smith H.A., Yusef-Zadeh F.
   <Astrophys. J. Suppl. Ser., 175, 147-164 (2008)>
   =2008ApJS..175..147R
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ADC_Keywords: Cross identifications ; Surveys ; Photometry, infrared

Mission_Name: Spitzer

Keywords: Galaxy: center - stars: late-type


Abstract:
    We have obtained Spitzer IRAC observations of the central
    2.0°x1.4° (~280x200pc) of the Galaxy at 3.6-8.0um. A
    point-source catalog of 1065565 objects is presented. The catalog
    includes magnitudes for the point sources at 3.6, 4.5, 5.8, and 8.0um,
    as well as JHKs photometry from Two Micron All Sky Survey (2MASS). The
    point-source catalog is confusion limited with average limits of 12.4,
    12.1, 11.7, and 11.2mag for [3.6], [4.5], [5.8], and [8.0],
    respectively. We find that the confusion limits are spatially variable
    because of stellar surface density, background surface brightness
    level, and extinction variations across the survey region. The overall
    distribution of point-source density with Galactic latitude and
    longitude is essentially constant, but structure does appear when
    sources of different magnitude ranges are selected. Bright stars show
    a steep decreasing gradient with Galactic latitude and a slow
    decreasing gradient with Galactic longitude, with a peak at the
    position of the Galactic center. From IRAC color-magnitude and
    color-color diagrams, we conclude that most of the point sources in
    our catalog have IRAC magnitudes and colors characteristic of red
    giant and asymptotic giant branch (AGB) stars.

File Summary:

FileName Lrecl Records Explanations
× 80 . This file × ReadMe 80 . This file × table2.dat 106 735020 Galactic Center IRAC 1 (3.6um) source lists × table3.dat 106 700923 Galactic Center IRAC 2 (4.5um) source lists × table4.dat 106 493207 Galactic Center IRAC 3 (5.8um) source lists × table5.dat 106 323512 Galactic Center IRAC 4 (8.0um) source lists × table6.dat 108 207 Galactic Center IRAC sub-array photometry × table7.dat 340 1065565 Galactic Center 2MASS/IRAC Catalog
See also: II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) II/293 : GLIMPSE Source Catalog (I+II+3D) (IPAC 2008) J/A+AS/97/587 : JHK photometry of Galactic center stars (Ruelas-Mayorga+ 1993) Byte-by-byte Description of file: table[2-5].dat
Bytes Format Units Label Explanations
1- 7 A7 --- --- [GC-IRAC-] 8 I1 --- Ch [1/4] Channel number: 1=3.6um, 2=4.5um, 3=5.8um, 4=8.0um 9 A1 --- --- [-] 10- 15 I06 --- ID Source identification number (1) 17 I1 --- --- Channnel number (repetition of Ch) 19- 20 I2 h RAh Hour of Right Ascension (J2000) 22- 23 I2 min RAm Minute of Right Ascension (J2000) 25- 29 F5.2 s RAs Second of Right Ascension (J2000) 32 A1 --- DE- Sign of the Declination (J2000) 33- 34 I2 deg DEd Degree of Declination (J2000) 36- 37 I2 arcmin DEm Arcminute of Declination (J2000) 39- 42 F4.1 arcsec DEs Arcsecond of Declination (J2000) 45- 56 F12.8 deg GLON Galactic longitude 58- 68 F11.8 deg GLAT Galactic latitude 70- 79 F10.3 mJy Flux Flux density in the channel wavelength 81- 89 F9.3 mJy e_Flux Uncertainty in Flux 91- 92 I2 --- N Number of observations of source 94-102 F9.1 --- S/N Signal-to-noise ratio 104-106 A3 --- Meth Method used to compute the flux (2)
Note (1): Name in Simbad is [RAS2008] GC-IRACc-NNNNNN where c is the channel number, and N the ID number Note (2): Method as follows: APC = Aperture Corrected Photometry. PRF = Point Response Function Fitting.
Byte-by-byte Description of file: table6.dat
Bytes Format Units Label Explanations
1- 3 I3 --- ID Source identification (NNN) 5- 9 A5 --- Field IRAC sub-array field (1) 11- 12 I2 h RAh Hour of Right Ascension (J2000) 14- 15 I2 min RAm Minute of Right Ascension (J2000) 17- 21 F5.2 s RAs Second of Right Ascension (J2000) 23 A1 --- DE- Sign of the Declination (J2000) 24- 25 I2 deg DEd Degree of Declination (J2000) 27- 28 I2 arcmin DEm Arcminute of Declination (J2000) 30- 33 F4.1 arcsec DEs Arcsecond of Declination (J2000) 35- 46 F12.8 deg GLON Galactic longitude 48- 58 F11.8 deg GLAT Galactic latitude 60- 65 F6.3 mag 3.6mag ? IRAC 3.6 micron band magnitude 67- 71 F5.3 mag e_3.6mag ? Uncertainty in 3.6mag 73- 78 F6.3 mag 4.5mag ? IRAC 4.5 micron band magnitude 80- 84 F5.3 mag e_4.5mag ? Uncertainty in 4.5mag 86- 90 F5.3 mag 5.8mag ? IRAC 5.8 micron band magnitude 92- 96 F5.3 mag e_5.8mag ? Uncertainty in 5.8mag 98-102 F5.3 mag 8.0mag ? IRAC 8.0 micron band magnitude 104-108 F5.3 mag e_8.0mag ? Uncertainty in 8.0mag
Note (1): Note as follows: sat = individual sub-array pointings. sgra = sub-array field centered on SgrA* quint = sub-array field centered on the Quintuplet cluster
Byte-by-byte Description of file: table7.dat
Bytes Format Units Label Explanations
1- 5 A5 --- --- [SSTGC] 7- 13 I07 --- SSTGC Source identification 15- 16 I2 h RAh Hour of Right Ascension (J2000) 18- 19 I2 min RAm Minute of Right Ascension (J2000) 21- 25 F5.2 s RAs Second of Right Ascension (J2000) 28 A1 --- DE- Sign of the Declination (J2000) 29- 30 I2 deg DEd Degree of Declination (J2000) 32- 33 I2 arcmin DEm Arcminute of Declination (J2000) 35- 38 F4.1 arcsec DEs Arcsecond of Declination (J2000) 41- 49 F9.5 deg GLON Galactic longitude 51- 58 F8.5 deg GLAT Galactic latitude 60 I1 --- 2+1 [0,1] satisfies the "2+1" criterion flag (1) 62 I1 --- loc [0,3] Note about source location (2) 64- 80 A17 --- 2MASS 2MASS identification (HHMMSSss+DDMMSSsA) 82- 87 F6.3 mag Jmag ?=-9.999 2MASS J band magnitude 89- 94 F6.3 mag e_Jmag ?=-9.999 Uncertainty in Jmag 96-103 F8.3 mag Hmag ?=-9.999 2MASS H band magnitude 105-110 F6.3 mag e_Hmag ?=-9.999 Uncertainty in Hmag 112-119 F8.3 mag Ksmag ?=-9.999 2MASS KS band magnitude 121-126 F6.3 mag e_Ksmag ?=-9.999 Uncertainty in Ksmag 128-130 A3 --- q2M [ABCDEFUXZ] 2MASS quality flag in J H K (3) 132-140 A9 --- --- [GC IRAC1-] 141-146 I06 --- ID1 ? Identification in Channel 1 (3.6um) 149-154 F6.3 mag 3.6mag ?=-9.999 Channel 1 magnitude at 3.6um 156-161 F6.3 mag e_3.6mag ?=-9.999 Uncertainty in 3.6mag 163-170 F8.1 --- SNR1 ?=-9.9 Channel 1 signal-to-noise 172 I1 --- f1 [0,4] Channel 1 flag (4) 174-175 I2 --- N1 Channel 1 Coverage (#frames at source position) 177-180 F4.2 --- M/N1 Channel 1 M/N ratio (5) 182-190 A9 --- --- [GC IRAC2-] 191-196 I06 --- ID2 ? Identification in Channel 2 (4.5um) 199-204 F6.3 mag 4.5mag ?=-9.999 Channel 2 magnitude at 4.5um 206-211 F6.3 mag e_4.5mag ?=-9.999 Uncertainty in 4.5mag 213-221 F9.1 --- SNR2 ?=-9.9 Channel 2 signal-to-noise 223 I1 --- f2 [0,4] Channel 2 flag (4) 225-226 I2 --- N2 Channel 2 Coverage (#frames at source position) 228-231 F4.2 --- M/N2 Channel 2 M/N ratio (5) 233-241 A9 --- --- [GC IRAC3-] 242-247 I06 --- ID3 ? Identification in Channel 3 (5.8um) 250-255 F6.3 mag 5.8mag ?=-9.999 Channel 3 magnitude at 5.8um 257-262 F6.3 mag e_5.8mag ?=-9.999 Uncertainty in 5.8mag 264-271 F8.1 --- SNR3 ?=-9.9 Channel 3 signal-to-noise 273 I1 --- f3 [0,4] Channel 3 flag (4) 275-276 I2 --- N3 Channel 3 Coverage (#frames at source position) 278-281 F4.2 --- M/N3 Channel 3 M/N ratio (5) 283-291 A9 --- --- [GC IRAC4-] 292-297 I06 --- ID4 ? Identification in Channel 4 (8.0um) 300-305 F6.3 mag 8.0mag ?=-9.999 Channel 4 magnitude at 8.0um 307-312 F6.3 mag e_8.0mag ?=-9.999 Uncertainty in 8.0mag 314-321 F8.1 --- SNR4 ?=-9.9 Channel 4 signal-to-noise 323 I1 --- f4 [0,4] Channel 4 flag (4) 325-326 I2 --- N4 Channel 4 Coverage (#frames at source position) 328-331 F4.2 --- M/N4 Channel 4 M/N ratio (5) 334-340 A7 --- ID6 Name from table6 (sub-array photometry) (6)
Note (1): the value '1' indicates that the source satisfies the GLIMPSE "2+1" criterion: M/N>=0.6 in one IRAC band, M/N>=0.4 in an adjacent band where M is the number of detections and N, the number of possible observations. Note (2): Flag as follows: 0 = source is located in areas of incomplete coverage. 2 = source is located within 40 arcmin on the Central Cluster. 3 = source is located within 42 arcmin of the Quintuplet Cluster. 1 = none of the above Note (3): JHK photometric quality flag from the 2MASS Catalog as follows: A = SNR>10 B = SNR>7 C = SNR>5 D = no SNR requirement E = poor profile-fit photometry F = detection without photometric uncertainty U = detection with upper limit on magnitude X = detection without brightness estimate ZZZ = no 2MASS counterpart Note (4): Flag as follows: 0 = source is not detected at the corresponding IRAC band. 1 = magnitude comes from PRF fitting algorithm. 2 = magnitude comes from aperture corrected measurement. 3 = magnitude is greater than corresponding saturation limit. 4 = magnitude comes from sub-array photometry. Note (5): Ratio between M number of detections over N number of possible observations (coverage). Note (6): for sources observed in the sub-array photometry, the name is * satNNN = source in individual sub-array pointings * sgraNNN = source in sub-array field centered on SgrA* * qintNNN = source in sub-array field centered on Quintuplet cluster
History: From electronic version of the journal ================================================================================ (End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 10-Jun-2009