SGRAREGCSC - Sgr A* Region Compact Radio Source Catalog

Overview

Recent broad-band 34- and 44-GHz radio continuum observations of the Galactic center have revealed 41 massive stars identified with near-IR (NIR) counterparts, as well as 44 proplyd candidates within 30 arcseconds of Sgr A*. Radio observations obtained in 2011 and 2014 have been used to derive proper motions of eight young stars near Sgr A*. The accuracy of proper motion estimates based on NIR observations by Lu et al. (2009, ApJ, 690, 1463) and Paumard et al. (2006, ApJ, 643, 1011) have been investigated by using their proper motions to predict the 2014 epoch positions of NIR stars and comparing the predicted positions with those of radio counterparts in the 2014 radio observations. Predicted positions from Lu et al. show an rms scatter of 6 milliarcseconds (mas) relative to the radio positions, while those from Paumard et al. show rms residuals of 20 mas. In the reference paper, the authors also determine the mass-loss rates of 11 radio stars, finding rates that are on average ~2 times smaller than those determined from model atmosphere calculations and NIR data. Clumpiness of ionized winds would reduce the mass loss rate of WR and O stars by additional factors of 3 and 10, respectively. One important implication of this is a reduction in the expected mass accretion rate onto Sgr A* from stellar winds by nearly an order of magnitude to a value of a few x 10^-7 solar masses per year.

The authors carried out A-array observations of the Galactic center region (VLA program 14A-232) in the Ka (9 mm, 34.5 GHz) band on 2014 March 9 in which they detected 318 compact radio sources within 30" of Sgr A*. The authors searched for NIR counterparts to these compact radio sources using high-angular resolution AOs-assisted imaging observations acquired with the VLT/NACO. A K_s-band (central wavelength 2.18 micron) image was obtained in a rectangular dither pattern on 2012 September 12. L'-band (3.8 micron) observations were obtained during various observing runs between 2012 June and September. The authors found that 45 of the compact radio sources had stellar counterparts in the K_s and L' bands.

This table contains the details of the 318 compact radio sources detected at 34.5 GHz and their NIR counterparts.

Catalog Bibcode

2015ApJ...809...10Y

References

Compact radio sources within 30" of Sgr A*: proper motions, stellar winds, and
the accretion rate onto Sgr A*.
    Yusef-Zadeh F., Bushouse H., Schodel R., Wardle M., Cotton W.,
    Roberts D.A., Nogueras-Lara F., Gallego-Cano E.
   <Astrophys. J., 809, 10 (2015)>
   =2015ApJ...809...10Y    (SIMBAD/NED BibCode)

Provenance

This table was created by the HEASARC in November 2016 based on CDS table J/ApJ/809/10, file table6.dat.

Parameters

Source_Number
A unique source number for each 34.5-GHz source in the catalog in order of increasing angular offset from Sgr A*.

Name
The name of the 34.5-GHz source created by the HEASARC using the style recommended by the CDS Dictionary of Nomenclature of Celestial Objects, viz., '[YBS2015] VLA nnn', where the prefix stands for 'Yusef-Zadeh, Bushouse, Schoedel 2015 Very Large Array' and nnn is the radio source number.

NIR_Name
The name of the NIR identified stellar counterpart source.

RA
The Right Ascension of the radio source in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.0001 seconds of time in the original table.

Dec
The Declination of the radio source in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.0001 arcseconds in the original table.

LII
The Galactic Longitude of the radio source.

BII
The Galactic Latitude of the radio source.

Galcen_Offset
The angular distance of the radio source position from that of Sgr A*, in arcseconds.

Error_Radius
The positional precision of the radio source, in arcseconds. This was given in milliarcseconds (mas) in the original table.

Major_Axis
The deconvolved radio source major axis (Theta_a), in mas.

Minor_Axis
The deconvolved radio source minor axis (Theta_b), in mas.

Position_Angle
The deconvolved radio source position angle, in degrees.

Flux_34p5_GHz
The peak intensity of the 34.5-GHz radio source, in mJy/beam.

Flux_34p5_GHz_Error
The uncertainty in the peak intensity of the 34.5-GHz radio source, in mJy/beam.

Int_Flux_34p5_GHz
The integrated intensity of the 34.5-GHz radio source, in mJy.

Int_Flux_34p5_GHz_Error
The uncertainty in the integrated intensity of the 34.5-GHz radio source, in mJy.

Flux_2p18_um
The flux density of the NIR counterpart to the 34.5-GHz radio source as measured in the K_S band (2.18 micron) with the VLT/NACO, in mJy.

Flux_2p18_um_Error
The uncertainty in the flux density of the NIR counterpart to the 34.5-GHz radio source as measured in the K_S band (2.18 micron) with the VLT/NACO, in mJy.

Flux_3p80_um
The flux density of the NIR counterpart to the 34.5-GHz radio source as measured in the L' band (3.80 micron) with the VLT/NACO, in mJy.

Flux_3p80_um_Error
The uncertainty in the flux density of the NIR counterpart to the 34.5-GHz radio source as measured in the L' band (3.80 micron) with the VLT/NACO, in mJy.

Ref_Codes
Codes for the references of individual sources, as follows:

    1 = Viehmann et al. (2005, A&A, 433, 117),
    2 = Eckart et al. (2004, ApJ, 602, 760),
    3 = Paumard et al. (2006, ApJ, 643, 1011),
    4 = Moultaka et al. (2009, ApJ, 703, 1635),
    5 = Yusef-Zadeh et al. (2014, ApJ, 792, L11).

Source_Flags
These flags indicate information on detections at NIR wavelengths or radio multiplicity, coded as follows:

    a = Detected only in L' band;
    b = Detected only in K_s band and faint source;
    c = Consists of multiple radio components.

Contact Person

Questions regarding the SGRAREGCSC database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:34:52 EDT