Observations of H1743-322 with the Sardinia Radio Telescope: upper limits

ATel #8849; E. Egron (INAF-OAC), M. Bachetti (INAF-OAC), A. Pellizzoni (INAF-OAC), A. Trois (INAF-OAC), M. N. Iacolina (INAF-OAC), M. Pilia (INAF-OAC), S. Loru (INAF-OAC), A. Navarrini (INAF-OAC), R. Ballhausen (Remeis/FAU/ECAP), S. Corbel (AIM/CEA), W. Eikmann (Remeis/FAU/ECAP), F. Fuerst (CalTech), V. Grinberg (MIT), I. Kreykenbohm (Remeis/FAU/ECAP), M. Marongiu (INAF-OAC), M. Nowak (MIT), A. Possenti (INAF-OAC), K. Pottschmidt (CRESST/GSFC/UMBC), J. Rodriguez (AIM/CEA), J. Wilms (Remeis/FAU/ECAP)
on 21 Mar 2016; 11:02 UT
Credential Certification: Elise Egron (egron@oa-cagliari.inaf.it)

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A new outburst of the Galactic black hole low-mass X-ray binary H1743-322 was reported on 2016 February 28 using Swift/BAT (Lin et al., ATel #8751), less than a year after its previous outburst (#7652). A series of Swift ToO observations were then performed in order to monitor the source (Yan et al., ATel #8800). A possible trend towards a state transition from hard to soft was noticed on March 7 and 10, which could indicate transient and flaring activities from the jets. Whereas the radio flux of this source in the C band (~7 GHz) is usually low (<~2 mJy), a maximum flux of 5.7 and 12.8 mJy/bm at 5.4 and 8.4 GHz respectively was reported in 2009 by Miller-Jones et al. (2012, MNRAS 421, 468)during this transition. We performed a short observation of this transient source on 2016 March 14 between UT 07:10 and 07:32, and then a longer one on 2016 March 18 between UT 05:13 and 06:55 with the Sardinia Radio Telescope (http://www.srt.inaf.it/), in the frame of the Early science program related to the monitoring of X-ray binaries with SRT (PI Egron). Observations were performed at 7.2 GHz, using the Sardara (Roach2) back-end and a bandwidth of 680 MHz. We performed rectangular On-the-fly maps in the RA and DEC directions (0.5 x 0.13 degrees). The source was not detected at the expected position. The flux upper limit at the source location is 2.3 mJy (1 sigma) considering only the second observation, and 2.1 mJy by including the first short observation. Note that the source, as was true for all sources close to the Galactic Center, was low in elevation at the SRT site, reaching a maximum of 18 degrees.