Search for X-ray Transients with MAXI Nobuyuki Kawai (Tokyo Tech) M. Serino (RIKEN), H. Negoro (Nihon U.) on behalf of the MAXI Team MAXI Instrumentation and operation Observations for GW 150914 and results in context Observations for GW 151226
Monitor of All-Sky X-ray Image Mission started August 2009 Ops approved until ~ March 2018 Matsuoka et al. 2009
Instruments and Observation 6 x 2 GSC (Gas Slit Camera) 2-20 kev, Time Resolution 50 µs Mihara+ 2011, Sugizaki+ 2011 2 x SSC (Solid-state Slit Camera) 0.7-7 kev, Time Resolution 5.865 s Tsunemi+ 2010, Tomida+ 2011 SSC (slit) collimator Proportional Counter slit
Nova-Alert System Negoro+ 2016, PASJ TKSC/JAXA RIKEN & MAXI MLs (& ATel/GCN) Nova Alert System < 10 sec (Real) ~ 1.5 h (Stored)
2.5 Blackholes MAXI Transients : 17 sources in 6 years J1932+091 J1659-152 (GRB 100925A) J1828-249 J1910-057 J1836-194 (Swift J1910.2-0546) J1647-227 J1735-304 (Swift J1734-3027?) J1421-613 J1305-704 GRB 121225A (Swift J1741.5-6548) J1409-619 J1543-564 MAXI J0158-744 J0556-332 1 White Dwarf, 6 Neutron Stars, 6 Black Hole Candidates, and 1 unknown
6 Black holes discovered by MAXI (out of 12 BHCs discovered since Aug 2009) 2.5 Blackholes Negoro et al. (2014) MAXI J1659-152 (GRB 100925A) 500 days MAXI 1305-704 MAXI 1836-194 MAXI 1543-564 MAXI J1910-057 (Swift J1910.2-0546) MAXI J1828-249 55500 56000 56500 2009.8 2014.4
MAXI watches through the whole Galaxy. 12 kpc 8.5 kpc F = al Edd /4pd 2 2.5 Blackholes a = 0.01-0.04 (Maccarone 2003) Soft-to-Hard Transition J1828 (l, b) = (8.1, -6.5) d > 12 kpc!? J1543 (l, b) = (325.1, -1.1) d > 12 kpc? (Stiele+ 2012) J1305 (l, b) = (304.2, -7.6) Negoro 2008
MAXI J0158-744: unique soft X-ray transient 8 MAXI GSC Allsky Image Galactic Coordinate 2011-11-11 05:05:59 (UT) GRB 111111A Soft X-ray transient ( < 5 kev) Swift follow-up lead to identification to a star near SMC (Be star at 60 kpc) Morii et al. 2013
MAXI J0158-744 9 X-ray Flux MAXI GSC X-ray light curve days MAXI SSC Morii et al. 2013 0.1 Swift XRT 1 10 Duration hour (1300 s <ΔT< 1.1 x 10 4 s) Extremely luminous 10 40 erg / s x100 solar mass Eddington luminosity supersoft X-ray source at late phase à white dwarf classical/recurrent nova? but x10 4 more luminous than known nova X-ray emission (shocked ISM? Li et al. 2012) 9
Nova (nuclear fusion) explosion Morii et al. (2013) rare WD-Be binary system (MAXI J0158-744) Be star Circumstellar disk Very massive O-Ne white dwarf Nova ignited with a less accumulation Luminous (100L E ) and Exploded out quickly Thermal Ne line Press Release from RIKEN (2013.11.14) 10 Credit: Takuya Ohkawa
Tidal Disruption Events - A star approaching to a giant black hole in the center of a galaxy is torn into pieces by the tidal force. The debris accretes to the black hole. - Long time monitoring of MAXI guarantees a single event, not one of the AGN activities. - MAXI detected three TDE during 2009-2012. Swift J1644+57 with Swift/BAT and MAXI/GSC 8 Burrows et al. Nature 2011 Swift J2058+05 with MAXI/GSC n T =-1.92 (-0.73/+0.58) 6 2011/5/20 2011/3/28 MAXI 2-10 kev Flux (mcrab) 4 2 0 55650 55750 55850 MJD (DAY)
GRB Reports to GCN Alert issued 12 sec GRB 160102A MAXI Trigger: XRT follow-up ToO: 160101A (+13.2 ks, afterglow detection) 160206A(+46.2 ks, 2 candidates) 151205C (+11.1 ks, No), 160102A (+10.8 ks, No) No ToO: 151216A, 160104B, 160107A (Fermi, CALET) Swift/BAT (faster) Trigger: detection: 151112A (BAT +36 s), 160227A (BAT +185 s) no detection: 151027A Swift-BAT Fermi INTEGRAL CALET + others MAXI 2-4 kev 4-10 kev 10-20 kev MAXI/All 2011 71 8 3 6 3 3.3% 2012 84 17 5 3 11 9.2% 2013 79 28 6 0 4 3.4% 2014 88 32 3 4 8 5.9% 2015 86 28 4 4 18 12.9% 2016 19 5 1 3 5 15.2% note: these numbers are not complete.
MAXI GRBs and transients (2 20 kev) : only MAXI (43) : MAXI + other (39 prompt + 7 afterglows) Serino et al. (2014) http://maxi.riken.jp/grbs/ 13
GRB localization with MAXI 14
MAXI Short Transient with no XRT counterparts GRB 150428C MAXI J1501-026 MAXI J1540-158 GRB 140814A MAXI J0545+043 GRB 130407A MAXI J1631-639 (l, b) = (139.1, +11.3) (354.6, +46.8) (351.6, +30.6) (139.9, +66.4) (201.1, -12.6) (26.4, +35.6) (324.4-10.8) 2-4 kev 4-10 kev 10-20 kev No flux in high energy flux 0.16 Crab 0.44 Crab band 0.1 Crab 0.23 Crab 0.2 Crab 0.17Crab 0.12 Crab 2015-04-28 2015-08-26 2015-03-11 2014-08-14 2014-04-12 2013-04-07 2011-04-29 GCN #17772 Atel #7954 GCN #17568 GCN #16686 ATel #6066 GCN #14359 ATel #3316 11 FOV MAXI light curves not corrected for collimator transmission 15
GW150914 (T0+4~92 min) Sun 2-20 kev 3-s upper limit: 0.1 counts s 1 cm -2 30 mcrab 1 10 9 erg s 1 cm -2 0 1 2 5 10 21 42 85 171 341 680 (Serino et al. GCN 19013)
GW150914 (T0+0~1 day) 0 11 31 74 157 326 659 1323 2663 5312 1058 2-20 kev 3-s upper limit: 8 mcrab 3 10 10 erg s 1 cm -2
MAXI on GW150914 1 scan ( 92 min) 5 min ~ 1 day Where there is no will, there might be a way to a GW star!?
MAXI observations for GW150914 Timescale (s) Flux (erg s 1 cm -2 ) Luminosity* (erg s 1 ) Radiated Energy (erg) E X /E GW 1 orbit 1000 < 9.5 10 10 < 1.9 10 46 < 1.9 10 49 < 3.5 10 6 1 day 8.6 10 4 < 2.3 10 10 < 4.6 10 45 < 4.0 10 50 < 7.4 10 5 10 days 8.6 10 5 < 0.8 10 10 < 1.6 10 45 < 1.4 10 51 < 2.6 10 4 * Distance 410 Mpc assumed Eddington luminosity for 62 M BH 10 40 erg s 1 Radiated energy in GW: E GW = DMc 2 5.4 10 54 erg
10-4 MAXI on GW150914 10-5 10-6 10-7 10-8 Flux (erg/s/cm^2) 10-9 10-10 10-11 10-12 10-13 10-14 10-15 10-2 10-1 10 0 10 1 10 2 10 3 10 4 10 5 10 6 Time since Trigger (sec)
10-4 MAXI on GW150914 10-5 10-6 10-7 Fermi GBM possible detection (extrapolated to 2 20 kev flux averaged over 1 second assuming photon index 1.4) 10-8 MAXI could have marginally detected GBM SGRB if it was in the field of view Flux (erg/s/cm^2) 10-9 10-10 10-11 10-12 10-13 10-14 10-15 10-2 10-1 10 0 10 1 10 2 10 3 10 4 10 5 10 6 Time since Trigger (sec)
Short GRB 050709 The only short GRB observed in soft X-ray HETE-2 Short hard pulse Villasenor et al. 2005 HST Fox et al. 2005 HETE-2 2 25 kev Chandra Soft extended emission z=0.160 Dwarf irregular galaxy SFR = 0.2 M sun /yr
MAXI sensitivity for SGRB in 10-4 10-5 10-6 10-7 GRB 050709 Short pulse GRB 050709 Extended emission GW range 10-8 MAXI could easily detect short pulse and soft extended emission of GRB 050709 Flux (erg/s/cm^2) 10-9 10-10 10-11 10-12 10-13 10-14 10-15 10-2 10-1 10 0 10 1 10 2 10 3 10 4 10 5 10 6 Time since Trigger (sec) GRB 050709 Afterglow (Chandra)
MAXI sensitivity for 10-4 10-5 10-6 GRB 050709 scaled to 100 Mpc SGRB in 10-7 GW range 10-8 Soft extended emission or X-ray afterglow of a short GRB at O2 BNS range may be detected by MAXI in the following scan Flux (erg/s/cm^2) 10-9 10-10 10-11 10-12 10-13 10-14 10-15 10-2 10-1 10 0 10 1 10 2 10 3 10 4 10 5 10 6 Time since Trigger (sec)
Summary MAXI scans about 60-80% of the sky in one orbit (92 min), and more than 90% in a day. We can provide a fast (<30 sec) alert for bright bursts. MAXI is detecting ~10 short transients per year. About half of them are confirmed as GRBs simultaneously detected by other satellites. There can be other class(es) of objects yet to be identified. MAXI discovered 17 new sources in 7 years including 6 black hole binaries and a white dwarf/be system. The latter exhibited a ultra-luminous explosion at ignition of a nova. A large fraction of GW150914 region was covered in 1000s, yielding a flux upper limit ~10 10 erg s 1 cm 2. MAXI can constrain the short GRB scenarios for DNS merger at <100 Mpc (O2 range) Instantaneous field of view of MAXI is 2% of the sky. iwf-maxi (FoV >10% sky) has been proposed.