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J/other/NewA/11.27  2MASS observation of BL Lac objects      (Chen+, 2005)

2MASS observation of BL Lac objects. Chen P.S., Fu H.W., Gao Y.F. <New Astronomy, 11, 27-42 (2005)> =2005NewA...11...27C
ADC_Keywords: BL Lac objects ; Infrared sources ; Photometry, infrared Keywords: galaxies: AGN, BL Lac object - infrared: galaxies Abstract: The 2MASS observations of known BL Lac objects are presented in this paper. The 2MASS associations for 511 BL Lac objects are identified. From the 2MASS near infrared two-color diagram it is seen that majority (about 70%) of objects are lying alone with or very close to the power law distribution implying that there is no need to invoke any significant radiation mechanism additional to a power law continuum for those sources. However, many sources (about 30%) are still located very close to the blackbody distribution indicative of the possible contributions from the host galaxies. In addition, the average spectral index derived for the near infrared region is 0.66±0.34 that is rather smaller than that from the previous results indicative of the possible influence from the host galaxies and/or from the lack or weakness of the radio emissions from most sources newly discovered by recent X-ray missions. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 151 511 2MASS observations of BL Lac objects
See also: II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) I/252 : The USNO-A2.0 Catalogue (Monet+ 1998) I/284 : The USNO-B1.0 Catalog (Monet+ 2003) J/other/NewA/11.557 : BL Lac objects infrared photometry (Chen+, 2006) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Seq Sequential number 5- 21 A17 --- Name BL Lac object Name 23- 35 A13 --- USNO USNO-A2 or USNO-B1 number 36 A1 --- n_USNO [AB] USNO-A2 (A) or USNO-B1 (B) 38- 39 I2 h RAh 2MASS Right ascension (J2000) 41- 42 I2 min RAm 2MASS Right ascension (J2000) 44- 48 F5.2 s RAs 2MASS Right ascension (J2000) 50 A1 --- DE- 2MASS Declination sign (J2000) 51- 52 I2 deg DEd 2MASS Declination (J2000) 54- 55 I2 arcmin DEm 2MASS Declination (J2000) 57- 60 F4.1 arcsec DEs 2MASS Declination (J2000) 62- 65 F4.2 arcsec r1 Distance between BL Lac object and related USNO source 67- 70 F4.2 arcsec r2 Distance between USNO source and related 2MASS source 72- 76 F5.2 mag Vmag ? V magnitude 78- 83 F6.3 mag Jmag 2MASS J magnitude 84 A1 --- n_Jmag [*] * indicates an upper limit for Jmag 86- 90 F5.3 mag e_Jmag ? rms uncertainty on Jmag 92- 97 F6.3 mag Hmag 2MASS H magnitude 98 A1 --- n_Hmag [*] * indicates an upper limit for Hmag 100-104 F5.3 mag e_Hmag ? rms uncertainty on Hmag 106-111 F6.3 mag Kmag 2MASS K magnitude 112 A1 --- n_Kmag [*] * indicates an upper limit for Kmag 114-118 F5.3 mag e_Kmag ? rms uncertainty on Kmag 120-124 F5.2 --- alpha(J-K) ? Power spectral index between J and K bands 126-130 F5.3 --- z ? Redshift 132-136 A5 --- Type Type of object (1) 139-141 A3 --- rad [*st ] Radio note (2) 142 A1 ---- u_Av [)] Uncertainty flag on Av 143-147 F5.3 mag Av ? Interstellar extinction coefficient Av 151 A1 --- Host [#] #: possible influence from the host galaxy
Note (1): Type of object as follows: BL = confirmed BL Lac object BL? = probable BL Lac object pBL = possible BL Lac object ? = questionable BL Lac object HP = highly polarized BL Lac object Note (2): Radio note as follows: * = source not detected in the radio band *st = source not detected in the radio band, star
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 23-Jun-2006
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