JACPOT XRB status

JACPOT XRB is a Target of Opportunity project, to be triggered by a detection of an outburst with an X-ray satellite (RXTE, SWIFT, INTEGRAL or MAXI), or, for the white dwarf system, on an AAVSO alert. On receipt of an alert, we will immediately begin monitoring with the VLA, and on detection of radio emission, the VLBA will begin its monitoring campaign. In 2009-2010, we monitored a white dwarf, a neutron star, and a black hole. In 2010-2011, we only monitored a black hole system, as our target neutron star proved too faint. In 2011-2012 we are currently allocated time to monitor a further black hole source.


2011-2012 Black Hole Status:
Not Yet Triggered


2010-2011 Black Hole Status:
Triggered on Aug 2011 Flare of MAXI J1836-194

  • 29-Aug-2011: MAXI detects new transient source (Negoro et al., ATel 3611).
  • 31-Aug-2011: MAXI detects a spectral transition from hard intermediate to soft intermediate state (Nakahira et al. ATel 3626).
  • 03-Sep-2011: JACPOT XRB triggered EVLA observations successfully detect unresolved radio activity at 4.6 & 7.9 GHz of 26.9±0.1 & 39.6±0.1 mJy (Miller-Jones et al., ATel 3628). Source position is RA (J2000) = 18:35:43.44587 ± 0.00009, Dec (J2000) = -19:19:10.462 ± 0.002. EVLA/VLBA observations ongoing.
  • 04-Sep-2011: First JACPOT XRB observations of MAXI J1836-194 with the VLBA. Source detected at both 8.4 and 2.3 GHz. Marginally-resolved compact jets seen at the higher frequency.
  • 18-Sep-2011: JACPOT XRB EVLA observations detect polarized emission from MAXI J1836-194.
  • 23-Sep-2011: RATAN-600 provide daily 4.8-GHz light curves from 2-22 September (Trushkin et al., ATel 3656).
  • 18-Oct-2011: Russell et al. report 2-12 micron detections of MAXI J1836-194 with VISIR on the VLT (ATel 3689).
  • 18-Oct-2011: Final JACPOT XRB observations taken with VLBA. Proper motion of binary system detected.
  • 01-Dec-2011: MAXI J1836-194 gets too close to the Sun for further X-ray observations; RXTE and Swift observations cease.
  • 03-Dec-2011: Final JACPOT XRB EVLA observation taken.


2010-2011 Neutron Star Status:
Triggered on 4U1820-30

Initial EVLA observations showed the source to be too faint for a VLBA campaign (0.1 mJy), so the observation campaign was halted.


2009-2010 Statuses:
All Triggered & Archived Here