Compact radio sources within 30″ of SGR A∗: Proper motions, stellar winds, and the accretion rate onto SGR A∗

F. Yusef-Zadeh, H. Bushouse, R. Schödel, M. Wardle, W. Cotton, D. A. Roberts, F. Nogueras-Lara, E. Gallego-Cano

    Research output: Contribution to journalArticlepeer-review

    29 Citations (Scopus)
    98 Downloads (Pure)

    Abstract

    Recent broadband 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 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. and Paumard et al. 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 mas relative to the radio positions, while those from Paumard et al. show rms residuals of 20 mas. We 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 × 10-7 M⊙ yr-1. Finally, we present the positions of 318 compact radio sources within 30″ of Sgr A∗, 45 of which have stellar counterparts in the NIR Ks (2.18 μm) and L′ (3.8 μm) bands.

    Original languageEnglish
    Article number10
    Pages (from-to)1-20
    Number of pages20
    JournalAstrophysical Journal
    Volume809
    Issue number1
    DOIs
    Publication statusPublished - 10 Aug 2015

    Bibliographical note

    Copyright 2015 The American Astronomical Society. First published in the Astrophysical journal, 809(1), 10, 2015, published by IOP Publishing. The original publication is available at http://www.doi.org/10.1088/0004-637X/809/1/10. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

    Fingerprint

    Dive into the research topics of 'Compact radio sources within 30″ of SGR A∗: Proper motions, stellar winds, and the accretion rate onto SGR A∗'. Together they form a unique fingerprint.

    Cite this