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J/ApJ/801/L26    Parameters of radio sources near Sgr A*    (Yusef-Zadeh+, 2015)

Radio continuum observations of the Galactic center: photoevaporative proplyd-like objects near Sgr A*. Yusef-Zadeh F., Roberts D.A., Wardle M., Cotton W., Schodel R., Royster M.J. <Astrophys. J., 801, L26 (2015)> =2015ApJ...801L..26Y (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Radio sources ; Stars, distances Keywords: Galaxy: center - H II regions - ISM: general - radio continuum: ISM - stars: protostars Abstract: We present radio images within 30" of Sgr A* based on recent VLA observations at 34 GHz with 7.8 µJy sensitivity and resolution of ∼88x46 mas. We report 44 partially resolved compact sources clustered in two regions in the E arm of ionized gas that orbits Sgr A*. These sources have size scales ranging between ∼50 and 200 mas (400-1600 AUs), and a bow-shock appearance facing the direction of Sgr A*. Unlike the bow-shock sources previously identified in the near-IR but associated with massive stars, these 34 GHz sources do not appear to have near-IR counterparts at 3.8 µm. We interpret these sources as a candidate population of photoevaporative protoplanetary disks (proplyds) that are associated with newly formed low mass stars with mass loss rates ∼10-7-10-6 M/yr and are located at the edge of a molecular cloud outlined by ionized gas. The disks are externally illuminated by strong Lyman continuum radiation from the ∼100 OB and WR massive stars distributed within 10" of Sgr A*. The presence of proplyds implies current in situ star formation activity near Sgr A* and opens a window for the first time to study low mass star, planetary, and brown dwarf formations near a supermassive black hole. The video abstract was created from a WorldWide Telescope tour file, which is available for download. Viewing the file requires a Windows PC with the WorldWide Telescope desktop client available at worldwidetelescope.org. Description: Radio continuum observations were carried out with the Karl G. Jansky Very Large Array (VLA) in its A-configuration at 34.5 GHz on 2014 March 9 (14A-232). We observed a field of view with a radius of 39'' centered on Sgr A* in the Ka band (8.7 mm) using the 3 bit sampler system, which provided full polarization correlations in four basebands, each 2 GHz wide, centered at 31.5, 33.5, 35.5, and 37.5 GHz. Each baseband was composed of 16 subbands 128 MHz wide. Each subband was composed of 64 channels, each 2 MHz wide. Objects: ---------------------------------------------------------- RA (ICRS) DE Designation(s) ---------------------------------------------------------- 17 45 40.04 -29 00 28.2 Sgr A* = NAME Sagittarius A ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 81 44 The Parameters of Gaussian Fitted 34 GHz Sources
See also: J/ApJ/699/186 : VLA observations of the Galactic center (Zhao+, 2009) J/A+A/511/A18 : NIR observations of stars near SgrA* (Schoedel+, 2010) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 3 A3 --- ID Detected radio source identifier ([YRW2015] PNN in Simbad) 4 A1 --- n_ID [a] Note on ID (1) 6- 7 I2 h RAh Hour of Right Ascension (J2000) 9- 10 I2 min RAm Minute of Right Ascension (J2000) 12- 18 F7.4 s RAs Second of Right Ascension (J2000) 20 A1 --- DE- Sign of the Declination (J2000) 21- 22 I2 deg DEd Degree of Declination (J2000) 24- 25 I2 arcmin DEm Arcminute of Declination (J2000) 27- 33 F7.4 arcsec DEs Arcsecond of Declination (J2000) 35- 39 F5.2 arcsec Dist Distance from Sgr A* 41- 45 F5.2 mas epos Positional accuracy 47- 49 I3 mas theta-a Semi-major axis 51- 53 I3 mas theta-b Semi-minor axis 55- 57 I3 deg PA Position angle 59- 63 F5.3 mJy/beam PInt Peak intensity 65- 69 F5.3 mJy/beam e_PInt Uncertainty in PInt 71- 75 F5.3 mJy Sint Integrated flux at 34 GHz 77- 81 F5.3 mJy e_Sint Uncertainty in Sint
Note (1): Note as follows: a = Spatially unresolved in one direction.
History: From electronic version of the journal
(End) Prepared by Tiphaine Pouvreau [CDS] 11-Sep-2017
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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