IXPE Cycle 2 ToO Triggers



Proposal Target ToO Prob Response Trigger 2-8keV Counts MDP99 Filter PI Exclusive Use IXPE Time [ks] NICER Time [ks] NuSTAR Time[ks] Swift Time [ks]

2006 1ES 1959+650 0.11 HIGH VHE flux of 0.5 Crab Unit 7.275 1.69 OPEN LAURA DI GESU 3 200 0 0 0
2006 MRK 501 0.09 HIGH VHE flux of 3 Crab Unit 4.196 2.23 OPEN LAURA DI GESU 3 0 0 0 0
2006 1ES 0033+595 0.08 HIGH VHE flux of 0.5 Crab Unit 3.079 2.64 OPEN LAURA DI GESU 3 0 0 0 0
2006 1ES 1011+496 0.05 HIGH VHE flux of 0.5 Crab Unit 0.67 5.57 OPEN LAURA DI GESU 3 0 0 0 0
2006 MRK 421 0.05 HIGH VHE flux of 3 Crab Unit 30.54 1 OPEN LAURA DI GESU 3 0 0 0 0
2006 1ES 1218+304 0.02 HIGH VHE flux of 0.5 Crab Unit 1.055 4.44 OPEN LAURA DI GESU 3 0 0 0 0

2017 GRS 1915+105 0.15 MEDIUM We plan to conduct the proposed IXPE observation during a period when the source exhibits an X-ray flare, surpassing the MAXI/GSC count rate of 0.2 cps. 6.2 1.5 OPEN KARRI KOLJONEN 100 0 0 0

2036 LSP/ISP BLAZAR 0.5 MEDIUM The ToO will be triggered if the flux of an LSP or an ISP blazar exceeds 4x10^{-11}erg s^{-1}cm{^-2} at 2-8 keV. We will use Fermi, VHE, and Swift Atels and our optical monitoring to identify a flaring LSP or ISP blazar. A Swift ToO will be triggered to measure the X-ray flux of the source if its gamma-ray flux exceeds 1x10^{-6}ph/s/cm^2 and R band brightness increases at least by 1 mag. 0.5 2.5 OPEN SVETLANA JORSTAD 900 0 20 14

2041 1A 0535+262 0.1 MEDIUM The criterion for the requested ToO observation triggering is based on the ongoing monitoring of the source with Swift (BAT) and MAXI. The observation will be triggered if the source luminosity will exceed the critical value of 5x10^37 erg/s. 200 1 OPEN SERGEY TSYGANKOV 6 400 0 0 0

2098 4U 1630-47 0.33 MEDIUM The IXPE and NICER observations will be triggered by a rapid increase in the MAXI 2-4~keV count rate from day-to-day, with rate differential exceeding 0.15 photons/s/cm^2/day. 33.67 0.6 OPEN JAMES STEINER 2 300 7 0 0

2102 SWIFT J0243.6+6124 0.03 MEDIUM The three observations will be triggered based on the MAXI and Swift-BAT monitoring programs. The observations should be triggered when the MAXI-GSC (2 20 keV) count rate is higher than 20 ct s^- 1 cm^-2 (or 1.2 ct s^-1 cm^-2 for Swift-BAT). We require one observation per 7 days. 900 0.17 GRAY HONGHUI LIU 300 0 0 0

2138 ACCRETING MSP 0.5 MEDIUM A flux 3E-10 erg/cm2/s (0.5-10 keV, = 10 mCrab), as detected by All Sky X-ray monitors. Monitoring with optical robotic telescopes will also be used to detect the onset of an outburst a few days before the source brightens in X-rays. 3.87 0.8 OPEN ALESSANDRO PAPITTO 6 900 0 0 0

2151 H1743-322 0.3 MEDIUM H1743-322 is detected in a rising outburst and exceeds 50 mCrab intensity from any monitoring mission (e.g., MAXI, Swift BAT, or NICER). 7.6 1.1 OPEN JAMES STEINER 2 200 5 20 0
2151 H1743-322 0.4 LOW (1) H1743-322 has exceeded 250 mCrab intensity during the outburst (e.g., seen by MAXI). (2) H1743-322 shows transition to thermal state, defined as MAXI color [4-10/2-4] < 0.25, or if NICER is monitoring, NICER color [4-12/2-4] < 0.2. (3) Thermal state persists for a duration >= 1 week (hardness criterion holds). 30 0.8 OPEN JAMES STEINER 2 120 5 20 0

2153 T CRB 0.5 HIGH After the onset of the nova event that will be known from optical observations. 4.2 3 OPEN MANEL ERRANDO 6 500 0 0 0

2156 AQL X-1 0.31 MEDIUM We will use the trigger from the XB-NEWS monitoring campaign with observed the source daily to detect start of the optical outburst. The optical outburst for this source is expected to start roughly 11 days before X-ray rise, which places proposed response time as a medium priority trigger. This trigger will observe the source in hard state. 33 1.4 OPEN YASH BHARGAVA 300 8 20 0
2156 AQL X-1 0.31 MEDIUM To trigger the soft state observation, we will use the MAXI daily lightcurves to monitor the transition of the source. Prior outbursts indicate that the transition in the source takes about 10 days which will be sufficient to trigger the soft state observation. 116.8 0.5 OPEN YASH BHARGAVA 100 2 20 0

2176 CANDIDATE NU BLAZAR 0.2 MEDIUM An IceCube real-time neutrino event alert and a nearby low-frequency-peaked blazar with a 2-10 keV flux >10^-11 erg s^-1 cm^-2 and a power-law index <=2 observed by Swift-XRT 0.074 14 OPEN QI FENG 200 0 0 0

2189 RELATIVISTIC_TDE 0.2 MEDIUM A relativistic jetted TDE with a 2-8 keV flux of >2e-11 erg/s/cm^2. 0.14 10 OPEN DHEERAJ PASHAM 150 45 0 0

2190 MRK 421 0.5 MEDIUM MAXI: > 0.27 photons cm-2 s-1 in the 2.0 20.0 keV band or Swift-XRT >85 cts/s in the 0.3 10 KeV band or NICER > 15e-10 erg cm-2 s-1 or VERITAS >5e-10 ph m-2 s-1 above 200 GeV 3.1 7 OPEN OLIVIER HERVET 150 0 0 28

2191 4U 1630-47 0.5 MEDIUM We will monitor the outburst of the source through MAXI and any other publicly available X-ray datasets. We will trigger the IXPE observation as soon as: 1) the source reaches a MAXI HR at which absorption lines have been previously detected or pure soft states, or 2) clear X-ray absorption lines are reported in the current outburst. 28.2 0.5 OPEN MAXIME PARRA 165 15 20 0
2191 H 1743-322 0.1 MEDIUM We will monitor the outburst of the source through MAXI and any other publicly available X-ray datasets. We will trigger the IXPE observation as soon as: 1) the source reaches a MAXI HR at which absorption lines have been previously detected or pure soft states, or 2) clear X-ray absorption lines are reported in the current outburst. 78.2 0.4 OPEN MAXIME PARRA 0 0 0 0
2191 GRO J1655-40 0.05 MEDIUM We will monitor the outburst of the source through MAXI and any other publicly available X-ray datasets. We will trigger the IXPE observation as soon as: 1) the source reaches a MAXI HR at which absorption lines have been previously detected or pure soft states, or 2) clear X-ray absorption lines are reported in the current outburst. 143.2 0.3 OPEN MAXIME PARRA 0 0 0 0
2191 IGR J17091-3624 0.1 MEDIUM We will monitor the outburst of the source through MAXI and any other publicly available X-ray datasets. We will trigger the IXPE observation as soon as: 1) the source reaches a MAXI HR at which absorption lines have been previously detected or pure soft states, or 2) clear X-ray absorption lines are reported in the current outburst. 17.3 0.7 OPEN MAXIME PARRA 0 0 0 0
2191 WIND EMITTING BHLMXB 0.25 MEDIUM We will monitor the outburst of the source through MAXI and any other publicly available X-ray datasets. We will trigger the IXPE observation as soon as: 1) the source reaches a MAXI HR at which absorption lines have been previously detected or pure soft states, or 2) clear X-ray absorption lines are reported in the current outburst. 4.7 1.4 OPEN MAXIME PARRA 0 0 0 0

2239 GS 1826-24 0.1 LOW We will regularly monitor the spectral state of the source by using the publicly available MAXI/GSC observations and trigger the Target of Opportunity observation when the source has transitioned to the hard state. The trigger probability is based on the time interval between 1) when it fully transitioned to the soft state and now, and 2) the time interval when it was in the hard state before. 2.6 4 OPEN MASON NG 630 0 0 0