Swift J1727.8-1613 absolute flux density and polarization measured with Submillimeter Array at 1.3mm
ATel #16230; S. D. Vrtilek (CfA), M. Gurwell (CfA), M. McCollough (CfA), R. Rao (CfA)
on 5 Sep 2023; 21:52 UT
Credential Certification: M. L. McCollough (mmccollough@head.cfa.harvard.edu)
Subjects: Sub-Millimeter, Black Hole, Transient, Variables
The hard X-ray transient Swift J1727.8-1613 (originally GRB 230824A: GCN #34536, #34537) has been undergoing a bright outburst at all wavebands, from X-rays (ATel #16205, #16206, #16207, #16210, #16215, #16217), infrared (#16225), optical (ATel #16208, #16209), radio at 5.25 and 7.45 GHz (ATel #16211) and at 5 and 8 GHz (Atel #16228).
Here we report detections with the SMA using 7 antennas tuned to LO 224.538 with 12 GHz bandwidth per side-band per polarization (lsb centered at 215.538; usb centered at 235.538) run in full polarization mode.
On 2023 Sep 03 (03:59:52 - 07:43:43 UTC) for 148.4 min with flux density averaged over both side-bands found at 173.37 +/- 8.66 mJy with a SNR of 495. A flat spectrum (side bands differed by 2mJy) with polarization fraction 2.1 +/- 0.2% and polarization angle -3.4+/-1.5 degrees.
On 2023 Sep 04 2023 Sep 04, (04:00:45 - 07:37:54 UTC) for 69.3 min with flux density averaged over both side-bands found at 150.12 +/- 10.51 mJy with a SNR of 349. A flat spectrum (side-bands differed by 2.6mJy) with polarization fraction 1.9 +/- 0.2% and polarization angle -4.1 +/-3.5 degrees.
The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica.
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