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J/AJ/127/3399     Sgr A* variability at cm wavelengths    (Herrnstein+, 2004)

The variability of Sagittarius A* at centimeter wavelengths. Herrnstein R.M., Zhao J.-H., Bower G.C., Goss W.M. <Astron. J., 127, 3399-3410 (2004)> =2004AJ....127.3399H
ADC_Keywords: Radio sources Keywords: accretion, accretion disks - black hole physics - Galaxy: center - radio continuum: galaxies Abstract: We present the results of a 3.3yr project to monitor the flux density of Sagittarius A* at 2.0, 1.3, and 0.7cm with the Very Large Array. Between 2000.5 and 2003.0, 119 epochs of data were taken with a mean separation between epochs of 8 days. After 2003.0, observations were made roughly once per month for a total of nine additional epochs. Details of the data calibration process are discussed, including corrections for opacity and elevation effects, as well as changes in the flux density scales between epochs. The fully calibrated light curves for Sgr A* at all three wavelengths are presented. Description: Data were collected in the A, B, C, D, and hybrid configurations of the VLA through projects AZ 128 (2000 June 21-September 26), AZ 129 (2000 October 5-2001 September 27), AZ 136 (2001 October 2-2003 January 4), and AZ 143 (2003 January 13-2003 October 14). From 2000.5 to 2003.0, the flux density of Sgr A* at 2.0, 1.3, and 0.7cm was measured roughly once per week (for a total of 119 epochs). Between 2003.0 and 2003.8, nine additional observations were made once per month in order to increase our sensitivity to long-term periodicities. Objects: ---------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------- 17 45 40.0 -29 00 28 Sgr A* = NAME SGR A* ---------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 56 128 Calibrated Flux Density of Sgr A* (with corrected values from erratum published in 2005, AJ, 129, 2511)
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 10 A10 "YYYY/MM/DD" Obs.Date Date of observation 12- 15 I4 d PDay Project day (1) 17- 20 F4.2 Jy F2.0cm ?=0.00 Flux density at 2.0cm (2) 22- 25 F4.2 Jy e_F2.0cm ?=0.00 The 1sigma error in F2.0cm (2) 27- 30 F4.2 Jy F1.3cm ?=0.00 Flux density at 1.3cm (2) 32- 35 F4.2 Jy e_F1.3cm ?=0.00 The 1sigma error in F1.3cm (2) 37- 40 F4.2 Jy F0.7cm ?=0.00 Flux density at 0.7cm (2) 42- 45 F4.2 Jy e_F0.7cm ?=0.00 The 1sigma error in F0.7cm (2) 47- 51 F5.2 --- Sp+Index ?=0.00 Spectral index (2) 53- 56 F4.2 --- e_Sp+Index ?=0.00 The 1sigma error in Sp+Index (2)
Note (1): Where Project day zero is 21 June 2000. Days refer to LST days such that observations occurred at roughly the same time each day. Note (2): Values of 0.00 in the table indicate that the parameter was not determined for that epoch.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 13-Jan-2007
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