Simultaneous Monitoring of X-Ray and Radio Variability in Sagittarius A*

Journal
Date Issued
2017
Author(s)
Capellupo, Daniel M.
•
Haggard, Daryl
•
Choux, Nicolas
•
Baganoff, Fred
•
Bower, Geoffrey C.
•
Cotton, Bill
•
Degenaar, Nathalie
•
Dexter, Jason
•
Falcke, Heino
•
Fragile, P. Chris
•
Heinke, Craig O.
•
Law, Casey J.
•
Markoff, Sera
•
Neilsen, Joey
•
•
Rea, Nanda
•
Yusef-Zadeh, Farhad
DOI
Abstract
Monitoring of Sagittarius A* from X-ray to radio wavelengths has revealed structured variability—including X-ray flares—but it is challenging to establish correlations between them. Most studies have focused on variability in the X-ray and infrared, where variations are often simultaneous, and because long time series at submillimeter and radio wavelengths are limited. Previous work on submillimeter and radio variability hints at a lag between X-ray flares and their candidate submillimeter or radio counterparts, with the long wavelength data lagging the X-ray. However, there is only one published time lag between an X-ray flare and a possible radio counterpart. Here we report nine contemporaneous X-ray and radio observations of Sgr A*. We detect significant radio variability peaking ≳ 176 minutes after the brightest X-ray flare ever detected from Sgr A*. We also report other potentially associated X-ray and radio variability, with the radio peaks appearing ≲ 80 minutes after these weaker X-ray flares. Taken at face value, these results suggest that stronger X-ray flares lead to longer time lags in the radio. However, we also test the possibility that the variability at X-ray and radio wavelengths is not temporally correlated. We cross-correlate data from mismatched X-ray and radio epochs and obtain comparable correlations to the matched data. Hence, we find no overall statistical evidence that X-ray flares and radio variability are correlated, underscoring a need for more simultaneous, long duration X-ray-radio monitoring of Sgr A*.
Volume
845
Issue
1
Start page
35
Uri
Issn Identifier
0004-637X
Ads BibCode
2017ApJ...845...35C
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

Capellupo_2017_ApJ_845_35.pdf

Description
Pdf editoriale
Size

3.01 MB

Format

Adobe PDF

Checksum (MD5)

8ac44df6890eea5fd1afa1627b1044ba

Loading...
Thumbnail Image
Name

1707.01937.pdf

Description
postprint
Size

1.01 MB

Format

Adobe PDF

Checksum (MD5)

a0791d3f89c5d9d5329145a379be74a9