PoS(INTEGRAL 2012)089 2 ks) and INTEGRAL http://pos.sissa.it/ ce. cadence monitoring of the in- ed with follow-up observations from ISGRI and JEM-X) to the 5 ToOs of 10 ks). The regions of e of the Galactic Center, and the ngular resolution at high energies e an increase in the discovery rate of month-long gaps between scans es. The data are public but we pro- of obscured high-mass X-ray bina- erved for 12.6ks per spacecraft rev- SFXTs), as well as other hard X-ray ies, and magnetars) that th INTEGRAL Workshop and celebration already exposed thanks to the Galactic bodaghee/isa. ∼ ive Commons Attribution-NonCommercial-ShareAlike Licen for position refinement and an initial spectrum (5–10 ToOs of Swift , on behalf of the ISA Collaboration ∗ [email protected] with XMM-Newton for deeper timing andinterest spectral are analysis (3– the Inner Perseus/NormaScutum/Sagittarius Arm Arms on tangents the on other. one Each arm sid olution region during is obs visibility periods. WhilePlane these Scans regions (GPS), are many transients are being missed because of any particular region. These fields feature a high density ries (HMXBs), including Supergiant Fast X-ray Transients ( emitting sources (e.g. microquasars, low-mass X-ray binar The INTEGRAL Spiral Arms (ISA) Key Programner consists Galactic spiral of arms high- (1.2 Ms inof AO9; new 0.6 Ms IGRs in with AO10) combin is well-suited to finding thankseven to in its crowded large regions field of of the view sky. and Our a primary objectives ar of new X-ray transients and better monitoringvide of mosaic known images sourc and source light curves in 4 energy bands ( community at http://ssl.berkeley.edu/ Speaker. ∗ Copyright owned by the author(s) under the terms of the Creat c of the 10th anniversary of the15-19 launch October 2012 Bibliotheque Nationale de France, Paris, France An INTEGRAL view of the high-energy sky (the first 10 years) - 9 UC Berkeley - Space Sciences Laboratory E-mail: Arash Bodaghee Results from the first year ofArms the Monitoring INTEGRAL Program Spiral

PoS(INTEGRAL 2012)089 tic Plane ). The centers ); and the tan- 20 keV allows ◦ ◦ Arash Bodaghee ycle 10 (2013). has been instru- ∼ ;0 ;0 ◦ ◦ Spiral Arms (ISA) (22.5 of the inner spiral arm (337.5 = ) = the transient population in b ) ; INTEGRAL b haracterize their behavior is l ; l aries (HMXBs) that populate INTEGRAL f known systems in the Galaxy. massive OB stars in the Milky ansient HMXBs where they are s much time to the Galactic anti- tes ( portunity (ToO) observations with their likely host regions in tandem e plane). XBs feature a compact object that tribution, and behavior of accreting ed into two large fields situated on y, and new hard X-ray sources will ecause of month-long gaps between GC at ( ally towards the spiral arm tangents INTEGRAL essence, the ISA program increases X-rays, iew: the tangent to the Inner Perseus e high-energy emission drops to the elds, and they serve as tracers of the ransients or SFXTs) that undergo brief en the most sensitive X-ray telescopes. es. The ring Program s of the plane during viewable periods ons must be performed soon (i.e., within -XRT). Operating above 5 keV which means that HMXBs can be ∼ Swift , 2 Monitoring of the Inner Spiral Arms” (PI: Bodaghee) ), they represent laboratories for studying accretion Rosat ⊙ M -ISGRI to peer through this obscuring material. Thanks to 10 & INTEGRAL INTEGRAL . While these regions are already exposed thanks to the Galac cycle 9 (2012), and has been approved for continuation into c XMM-Newton INTEGRAL and Our observing program called “ The objectives of the ISA program are an improved sampling of The inner spiral arms feature the highest formation rates of Photoelectric absorption along the Galactic Plane, especi Hence, the best way to discover these kinds of sources and to c This program consists of 1.2 Ms worth of regular scans by the spiral arms and a morecompact complete objects picture in of our the Galaxy. number, dis 2. The ISA program Scans (GPS; PI: Bazzano), many transientsscans are of being missed any b particularcenter region, as and it because does the tothe GPS source-rich observing devotes regions a frequency of of thecompared inner scientifically-valuable with disk. the region GPS In (which remains useful for the rest of th began in program represents such alikely campaign. to We be will found, search i.e.,be for the observed new inner in spiral tr the arms softSwift X-rays of thanks the to Milky approved Wa Target of Op Way. Some of thesethe stars dust-obscured regions evolve of to theaccretes become Galactic from high-mass Plane. a X-ray massive Because bin donor HM star ( Results from the first year of the INTEGRAL Spiral Arms Monito 1. Introduction where HMXBs tend to cluster, blocks X-rays below physics under extreme gravitationalrecent and star-formation electromagnetic history of fi the Milky Way. gent to the Scutum and Sagittarius arms on the left side of the difficult to detect in soft X-ray surveys (e.g., mental in discovering HMXBs—more than doublingMany the of number them o are transient emittersand (supergiant unpredictable fast flaring X-ray episodes, t so follow-upseveral observati hours or days)quiescent after levels that their are discovery. often too faint Otherwise, to be th detected by ev through a campaign dedicated towith the rapid hard follow-up X-ray observations monitoring from of soft X-ray telescop the soft gamma-ray imager tangents of the Galaxy.opposite The sides Region of the of Galactic Interest Centerand (RoI) (GC) Norma from is arms our divid on point the of right v side of the GC at Galactic coordina its wide field of view (FoV) and spatial resolution in the hard PoS(INTEGRAL 2012)089 bin of ◦ ner spiral Arash Bodaghee piral arm tangents n at least 3 times 0.02 SFXTs/deg for the rest llustrated in Fig. 1. There are tected HMXBs in a 15 MXBs/deg) compared with the ISGRI partially-coded FoV. The urces, around half of which were he SFXT population is even more symbols. Other Galactic objects (cata- r unclassified HMXBs; and magenta for d FoV. .8 ks arranged in a hexagonal pattern observes one (or both) of these fields on-contiguous months per year. Each ring Program urces detected by ISGRI to date. The upper mbolize sources awaiting classification. r panel displays the Inner Perseus/Norma Arms. rcles represent low and high-mass X-ray binaries: re labelled with magenta diamonds. Extragalactic 3 INTEGRAL 3 days), ∼ 20 candidate SFXTs in the Galaxy, 14 are located within the in . ∼ -wide combined, i.e., wider than that shown in Fig. 1) contai -ISGRI significance maps (3Ms; 18–40keV) of a section of the s ◦ INTEGRAL INTEGRAL For each spacecraft revolution ( The density of hard X-ray sources in the inner spiral arms is i as many hard X-ray detectedaverage HMXBs for per the longitude rest degree of (0.7confined the H to Galactic the Plane arms: (0.2 of HMXBs/deg). T arms. This amounts toof 0.3 the SFXTs/deg plane. in Thediscovered the by survey arms regions compared contain with hundreds of other so as long as they areobservation visible: lasts the 12.6 ks visibility consisting period of lasts 4–6 seven pointings n of 1 36 HMXBs in this imagetargeted which regions represents (50 less sky area than the longitude which is roughly the width of the ISGRI fully-code objects are denoted by magenta ellipses. Magenta crosses sy of these fields were chosen to maximize the number of ISGRI-de targeted in the ISA programpanel along presents the with Scutum/Sagittarius the Arms, locations while of the all lowe so red for SGXBs (the SFXTsLMXBs. are boxed); green Unclassified for X-ray BEXBs; binariesclysmic white variables, are fo magnetars, shown supernova remnants, as etc.) magenta a plus The arrows indicate the direction to the Galactic Center. Ci Figure 1: Results from the first year of the INTEGRAL Spiral Arms Monito PoS(INTEGRAL 2012)089 ilar rs (AXPs), intings and 10 mCrab in ∼ revolution 1143 Arash Bodaghee bodaghee/isa). ∼ er observing cadence of 5 mCrab at the end of the strating how X-ray sources INTEGRAL ∼ –40, and 40–100 keV) soon after enter. The center of the hexagonal o provide mosaic images and light on, and roved study of their long-term tim- , but also: low-mass X-ray binaries tes from f reduced data products from JEM-X ves (in the same energy bands as above) the fully-coded FoV is The top row presents JEM-X (3–10keV) actic nuclei (AGN) viewed through the ring Program line (http://ssl.berkeley.edu/ 4 47, using all ISA observations to date. These figures, and sim − QSOs); cataclysmic variables (CVs); anomalous X-ray pulsa µ after each observation in order to overlap JEM-X and ISGRI po ◦ Examples of reduced data products from the ISA progrom deomn Among the benefits of the ISA program is that it provides a high Figure 2: are monitored in severaland energy bands ISGRI and over (18–40keV) the long significance term. maps in Galactic coordina Results from the first year of the INTEGRAL Spiral Arms Monito with one pointing at each cornerpattern of is the offset hexagon by and 1 one at the c magnetars, and soft-gamma repeaters (SGRs); and active gal (MJD55979.377). The bottomfor row one displays of the the detected X-ray sources,images 4U light and 1630 light cur curves from other sources, are available on to reduce imaging systematics. The limiting sensitivity in entire program. We elected tocurves make of all detected data sources public, in buteach 4 we observation is als energy completed. bands Figure (3–10, 2and 10–25, ISGRI. presents examples 18 o known variable sources in theing spiral and arms, spectral permitting evolution. an(LMXBs); Variable imp microquasars sources ( include HMXBs the JEM-X and ISGRI bands after a single hexagonal observati PoS(INTEGRAL 2012)089 INTEGRAL INTEGRAL Arash Bodaghee . bodaghee/isa. The main Swift ∼ een performed thus far and and bodaghee/isa (Fig. 3). Most of eley.edu/ ∼ ed 730 ks of our program in AO9 bservations during 2013. MAXI pectral data from our roved for continuation into AO10. (3–10 and 10–25keV), as well as light se long gaps in the source light curve ier to locate periodic signals such as ors arms are observed more often (in both nsitive observations of SN 2011fe and lated to changes in the accretion rate). ring Program be useful when comparing the transient of the compact object and the geometry monitoring of the Galactic Bulge [1] by n they are currently with the . From here, one can find images of each rkeley.edu/ 5 INTEGRAL Web page of the ISA program located at http://sprg.ssl.berk Around 40% of ISA observations (470 ks of 1.2 Ms) for AO9 have b panel presents the welcomeobservation page from ISGRI which (18–40 lists and thecurves 40–100keV) in main and those results bands from for JEM-X all detected sources. Galactic Plane. Known sources in thetotal direction exposure of and in the the spiral frequency ofGPS. the Having observations) additional tha data points betweenallows what are us otherwi to track theirThese luminosity extra variations observations (which enlarge are the re pulsation and baseline orbital making periods it which tell eas of us the about system, the respectively. nature We will add to the Figure 3: Results from the first year of the INTEGRAL Spiral Arms Monito extending the observations to higher longitudespopulation which will of the bulge with that of the disk. The timing and s observations complement those of existing hard X-ray monit our observations were interrupted or delayeddue due to to a time-se large Solarwill flare be in carried 2012 over March. into As AO10.This a means Furthermore, result, a ISA total an has exposure estimat been time app of 1.3 Ms is dedicated to ISA o 3. Preliminary results reduced data products are available at http://sprg.ssl.be PoS(INTEGRAL 2012)089 1621 − 0546 dur- − gy emission Arash Bodaghee ng strategy has proven successful vations of the Scutum/Sagittarius owever, the detection of a cyclotron 3624, and Swift J1910.2 rd X-ray transient IGR J18179 − ht curve and spectral data that we have ring Program 6, 595 , 4328, 1 langa, M. 2012, A&A, 545, A83 Tel, 4360, 1 945, 1 947, 1 6 47, IGR J17091 − revolutions. 600 X-ray sources in the RoI, we were able to confirm high-ener INTEGRAL ∼ While we have not yet discovered a new transient, our observi [1] Kuulkers, E., Shaw, S. E., Paizis, A., et al. 2007, A&A, 46 [2] Bodaghee, A., Popp, A., Grinberg, V., et[3] al. 2012, Bodaghee, ATel, 3 A., Bozzo, E., Tomsick, J. A., et al. 2012, ATel [5] Tuerler, M., Chenevez, J., Bozzo, E., et[6] al. 2012, Bozzo, ATel, E., 3 Ferrigno, C., Türler, M., Manousakis, A., & Fa [4] Bodaghee, A., Kuulkers, E., Tomsick, J. A., et al. 2012, A from the microquasar candidates 4U 1630 ing their recent hard states [2, 3, 4]. The discovery of the ha [5] preceded our scheduled ISA observations byfeature a [6] few hours. was H madeArms possible in thanks subsequent to ISA monitoring obser Results from the first year of the INTEGRAL Spiral Arms Monito References in achieving our other objectives. Onaccumulated top for of the the wealth of lig