Search for thermonuclear x-ray bursts with Integral

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1 Sarch for thrmonuclar x-ray bursts with Intgral, Vinna Tchnical Univrsity Tutors: Clia Sanchz & Erik Kuulkrs

2 Contnts What? X-ray binaris X-ray bursts Intgral and its instrumnts Why? th Galactic Bulg Monitoring Program IBIS and its advantags vs. JEMX How? Sarch for bursts in dtctor lightcurvs rconstruct a snapshot of th burstr dtrmin th burst proprtis

Mass transfr via Roch-lob ovrflow Proprtis of LMXBs : Accrtion disk bright radiation hatd disk mattr

3 Low mass X-ray binaris LMXBs consist of a compact objct black hol or nutron star, and a low mass companion (old star or whit dwarf ). Mass transfr via Roch-lob ovrflow Proprtis of LMXBs : Accrtion disk bright radiation hatd disk mattr that hits CO Luminosity 250 to L sol orbital priods 11 min to 17 d soft X-ray spctra (kt 10 kv) ~ 160 known, 130 in Milky Way Pictur of th Galactic Plan in X-rays

4 Typ I X-ray bursts Thrmonuclar burning on th surfac of a NS Accumulation of ful on th NS surfac (accrtion) Cration of a thin shll gtting dnsr and hottr Thin shll Instability triggrs thrmonuclar runaway Proprtis of Typ I bursts: accumulation for svral hours to days burst durations ~ sc (dpnds on ful-mix) nrgy rlas is nuclar, not gravitational ~ 70 LMXBs known to b Burstrs Lightcurvs of an X-ray burst in diffrnt

Intgral and on-board Instrumnts Th Intrnational Gamma Ray Astrophysics Laboratory Th mission: Obsrvation of Gamma Ray Phnomna combining fin spctroscopy with imaging and positioning of th sourcs.

5 Intgral and on-board Instrumnts Th Intrnational Gamma Ray Astrophysics Laboratory Th mission: Obsrvation of Gamma Ray Phnomna combining fin spctroscopy with imaging and positioning of th sourcs. Scinc goals: Compact objcts Binaris, Black Hol Candidats, Extragalactic sourcs AGNs, Syfrt Galaxis, Stllar objcts Wolf Rayt Stars, Nova, Suprnova, Obsrvation of Galactic Plan and Cntr Rgion Dtction of Gamma Ray Bursts Th Instrumnts: IBIS Imagr on Board th Intgral Satllit - high rs Imags of Gamma-ray objcts - Fild of Viw 9 x 9-12 arcmin angular rs ISGRI Intgral soft gamma-ray Imagr CdT smiconductor dtctor kv PICsIT Pixllatd Imagr CsI Tlscop CsI scintillator crystals 200 kv 10 MV JEMX Joint Europan Monitor for X-rays - High rs Imags in th X-ray band - FOV 4.8 diamtr kv -3 arcmin angular rs th IBIS dtctor array Morovr SPI, a spctromtr, and OMC

6 ks) invstigat th sourc variability and transint activity on short and long tim scals 3 Sasons of Obsrvations (Rvolutions 288-492) Total

6 Th Galactic Bulg Monitoring Program Monitoring of th Galactic Bulg Rgion with INTEGRAL, it is a rich host of variabl X- and Gamma-ray point sourcs Obsrv th rgion rgularly at hard X-rays and Gamma-rays, ~ vry 3 days (12.6 ks) invstigat th sourc variability and transint activity on short and long tim scals 3 Sasons of Obsrvations (Rvolutions ) Total Covrag around th Galactic Cntr of 29 with IBIS/ISGRI 6 with JEMX IBIS has a widr FOV than JEMX! It covrs about half of th total X-ray binary population Rv IBIS/ISGRI kv Mosaic Imag

Burst Dtction Typ I bursts ar mainly sn in soft X-rays obsrvd BB tmpraturs : 1-3 kv JEMX In th 3 sasons of th monitorig program JEMX saw 110 Typ I X-ray bursts! W want to look at thm with IBIS!

7 Burst Dtction Typ I bursts ar mainly sn in soft X-rays obsrvd BB tmpraturs : 1-3 kv JEMX In th 3 sasons of th monitorig program JEMX saw 110 Typ I X-ray bursts! W want to look at thm with IBIS! widr FOV W look at th IBIS/ISGRI Dtctor Lightcurvs of a singl obsrvation: Cration of Histograms bin = 1-2 s Computation of avrag count rat N and th corrsponding standard dviation σ whn condition N " N! 6 ó for count rat N in on bin holds... Burst!

8 Imag Rconstruction W dfin a Good Tim Intrval which includs only th tim of th burst Cration of sky imag of th momnt of th burst with OSA (Offlin Scinc Analysis Softwar, V 6.0). th burst of Rv 351, obsrvation 25 in th histogram Sky Imag (significanc) of th momnt of th burst. Sky Imag (significanc) with intgration tim of th whol

9 Dtrmining burst proprtis Th burst shap is givn by th following formula : Fast ris with xponntial dcay W fit this xponntial dcay to burst shaps in th histograms:! t n+h " ô n... avrag count rat h... hight of th burst abov avarag τ... man liftim Calculation of th intgratd flux E b of th burst vnt

10 Projct Status First Rsults: W wr abl to idntify th sourcs of 56 bursts within th data of 3 sasons (MJD ) of th GBMP by now: Th bursts com from 8 diffrnt sourcs 35 bursts (62%) com from only on sourc, GX SGR is a soft Gamma-ray rpatr, not a typ I X-ray burstr still to do: OSA didn t find anything, but w hav a possibl Sourc idntify what OSA lft ovr! w focusd on th high significant bursts (>6) du to imag rconstruction. idntify as wll th faintr ons dtrmin thir proprtis Sourc Rv ScW IJD GX A GX GX U GX GX GX GX GX U GX GX SGR SGR GX GX GX GX GX GX GX U GX SAX J NEW GX GX U U SAX J GX GX U GX U GX SGR GX GX GX GX SGR GX GX GX GX GX GX

11 Problms with Imag Rconstruction IBIS is a Codd Mask Instrumnt Imags of sourcs hav to b rconstructd by Th Analysis Softwar! Problms with OSA: A crtain amount of photon counts (xposur tim) is ncssary so imag rconstruction works Nw sourcs arn t always found by th Softwar, spcially in th partially codd FOV can b found by looking for ghosts in th imag Imag of a potntial nw sourc not dtctd By OSA. It s ghosts whr not automatically rmovd during Imag Rconstruction.

12 Thank You!

orintation of th satllit & analysis of data from th dtctor dtrmin

13 CODED MASK TECHNIQUE NO MIRRORS IN GAMMA RAYS NO OPTICAL IMAGES CODED MASK: Mask th aprtur of th tlscop Masur its shadow on th dtctor orintation of th satllit & analysis of data from th dtctor dtrmin position & intnsity of sourcs imag of th obsrvd sky: a. Codd mask b. Dtctor c. Fild of viw

14 ANTI-COINCIDENCE SYSTEM Blockd photon Valid photon MASK Vtod photon or particl ANTI-COINCIDENCE

Laura Barragán. Universidad Complutense de Madrid

Laura Barragán. Universidad Complutense de Madrid . Universidad Complutense de Madrid Tutors: Erik Kuulkers & Peter Kretschmar INTEGRAL: International Gamma-Ray Astrophysics Laboratory The payload The mission The project IBIS (Imager on-board the Integral