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Table · dataset · 2015

VLA, ALMA and SMA monitoring of Sgr A*

Listed in IVOA Registry (Virtual Observatory)

We report new observations with the Very Large Array, Atacama Large Millimeter Array, and Submillimeter Array at frequencies from 1.0 to 355GHz of the Galactic Center black hole, Sagittarius A*.

Description

These observations were conducted between 2012 October and 2014 November. While we see variability over the whole spectrum with an amplitude as large as a factor of 2 at millimeter wavelengths, we find no evidence for a change in the mean flux density or spectrum of Sgr A* that can be attributed to interaction with the G2 source.

The absence of a bow shock at low frequencies is consistent with a cross-sectional area for G2 that is less than 2x10^29^cm2. This result fits with several model predictions including a magnetically arrested cloud, a pressure-confined stellar wind, and a stellar photosphere of a binary merger. There is no evidence for enhanced accretion onto the black hole driving greater jet and/or accretion flow emission.

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Finally, we measure the millimeter wavelength spectral index of Sgr A* to be flat; combined with previous measurements, this suggests that there is no spectral break between 230 and 690GHz. The emission region is thus likely in a transition between optically thick and thin at these frequencies and requires a mix of lepton distributions with varying temperatures consistent with stratification.

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Radio
Provenance · 1 source records, 8 field assertions
SourceKeyLast seenRaw
IVOA Registry (Virtual Observatory)ivo://cds.vizier/j/apj/802/6912 d agoJSON v1
FieldAssertionExtractorEvidence
access_levelsource · IVOA Registryconnector:ivoa_registry@1.0.0
concepts[field].local:field:astronomymapping · IVOA Registryconnector:ivoa_registry@1.0.0
concepts[modality].ivoa_waveband:radiosource · IVOA Registryconnector:ivoa_registry@1.0.0
descriptionsource · IVOA Registryconnector:ivoa_registry@1.0.0rr.resource.res_description
license_textsource · IVOA Registryconnector:ivoa_registry@1.0.0
publication_datesource · IVOA Registryconnector:ivoa_registry@1.0.0
titlesource · IVOA Registryconnector:ivoa_registry@1.0.0rr.resource.res_title
updated_datesource · IVOA Registryconnector:ivoa_registry@1.0.0