Acciari, V. A.
Aliu, E.
Arlen, T.
Bautista, M.
Beilicke, M.
Benbow, W.
Boettcher, M.
Bradbury, S. M.
Bugaev, V.
Butt, Y.
Butt, Y.
Byrum, K.
Cannon, A.
Cesarini, A.
Chow, Y. C.
Ciupik, L.
Cogan, P.
Colin, P.
Cui, W.
Daniel, M.
Dickherber, R.
Ergin, Tülün
Falcone, A.
Fegan, S. J.
Finley, J. P.
Fortin, P.
Fortson, L.
Furniss, A.
Gall, D.
Gillanders, G. H.
Grube, J.
Guenette, R.
Gyuk, G.
Hanna, D.
Hays, E.
Holder, J.
Horan, D.
Hui, C. M.
Humensky, T. B.
Kaaret, P.
Karlsson, N.
Kieda, D.
Kildea, J.
Konopelko, A.
Krawczynski, H.
Krennrich, F.
Lang, M. J.
LeBohec, S.
Maier, G.
McCann, A.
McCutcheon, M.
Millis, J.
Moriarty, P.
Mukherjee, R.
Nagai, T.
Ong, R. A.
Otte, A. N.
Pandel, D.
Perkins, J. S.
Perkins, J. S.
Pohl, M.
Quinn, J.
Ragan, K.
Reyes, L. C.
Reynolds, P. T.
Roache, E.
Rose, H. Joachim
Schroedter, M.
Sembroski, G. H.
Smith, A. W.
Steele, D.
Stroh, M.
Swordy, S.
Theiling, M.
Toner, J. A.
Varlotta, A.
Vassiliev, V. V.
Wagner, R. G.
Wakely, S. P.
Ward, J. E.
Weekes, T. C.
Weinstein, A.
White, R. J.
Williams, D. A.
Wissel, S.
Wood, M.
Zitzer, B.
We present results from a long-term monitoring campaign on the TeV binary LSI +61 degrees 303 with VERITAS at energies above 500 GeV, and in the 2-10 keV hard X-ray bands with RXTE and Swift, sampling nine 26.5 day orbital cycles between 2006 September and 2008 February. The binary was observed by VERITAS to be variable, with all integrated observations resulting in a detection at the 8.8 sigma (2006/2007) and 7.3 sigma (2007/2008) significance level for emission above 500 GeV. The source was detected during active periods with flux values ranging from 5% to 20% of the Crab Nebula, varying over the course of a single orbital cycle. Additionally, the observations conducted in the 2007-2008 observing season show marginal evidence (at the 3.6 sigma significance level) for TeV emission outside the apastron passage of the compact object around the Be star. Contemporaneous hard X-ray observations with RXTE and Swift show large variability with flux values typically varying between 0.5 and 3.0 x 10(-11) erg cm(-2) s(-1) over a single orbital cycle. The contemporaneous X-ray and TeV data are examined and it is shown that the TeV sampling is not dense enough to detect a correlation between the two bands.


Frequency-resolved spectroscopy of XB1323-619 using XMM-Newton data: detection of a reflection region in the disc
Balman, Şölen (Oxford University Press (OUP), 2010-09-21)
We present the frequency-resolved energy spectra (FRS) of the low-mass X-ray binary dipper XB1323-619 during persistent emission in four different frequency bands using an archival XMM-Newton observation. FRS method helps to probe the inner zones of an accretion disc. XB1323-619 is an Atoll source and a type-I burster. We find that the FRS is well described by a single blackbody component with kT in a range 1.0-1.4 keV responsible for the source variability in the frequency ranges of 0.002-0.04 and 0.07-0.3...
VERITAS discovery of > 200 GeV gamma-ray emission from the intermediate-frequency-peaked BL Lacertae object W Comae
Acciari, V. A.; et. al. (IOP Publishing, 2008-09-10)
We report the detection of very high energy gamma- ray emission from the intermediate- frequency- peaked BL Lacertae object W Comae (z = 0.102) by VERITAS. The source was observed between 2008 January and April. A strong outburst of gamma-ray emission was measured in the middle of March, lasting for only 4 days. The energy spectrum measured during the two highest flare nights is fit by a power law and is found to be very steep, with a differential photon spectral index of Gamma = 3.81 +/- 0.35(stat) +/- 0.3...
Optical observations of the Be/X-ray transient system KS 1947+300
Kiziloglu, U.; Baykal, Altan; Kiziloglu, N. (Wiley, 2007-01-01)
ROTSE-IIId observations of the Be/X-ray transient system KS 1947+300 obtained between September 2004 and December 2005 make it possible to study the correlation between optical and X-ray activity. The optical outburst of 0.1 mag was accompanied by an increase of the X-ray flux in the 2004 observations. A strong correlation between the optical and X-ray light curves suggests that the neutron star directly accretes from the outflowing material of the Be star. The nearly zero time lag between X-ray and optical...
Comprehensive analysis of the transient X-ray pulsar MAXI J1409 619
Donmez, C. K.; Serim, Muhammed Miraç; Inam, S. C.; Sahiner, S.; Serim, D.; Baykal, Altan (Oxford University Press (OUP), 2020-08-01)
We probe the properties of the transient X-ray pulsar MAXI J1409-619 through RXTE and Swift follow-up observations of the outburst in 2010. We are able to phase-connect the pulse arrival times for the 25 d episode during the outburst. We suggest that either an orbital model (with P-orb similar or equal to 14.7(4) d) or a noise process due to random torque fluctuations (with S-r approximate to 1.3 x 10(-18) Hz(2) S-2 Hz(-1)) is plausible to describe the residuals of the timing solution. The frequency derivat...
Optical imaging and spectroscopic observation of the galactic supernova remnant G85.9-0.6
GÖK, FATMA; Sezer, A.; Aktekin, E.; Guever, T.; Ercan, N. (Springer Science and Business Media LLC, 2009-11-01)
Optical CCD imaging with H alpha and [SII] filters and spectroscopic observations of the galactic supernova remnant G85.9-0.6 have been performed for the first time. The CCD image data are taken with the 1.5 m Russian-Turkish Telescope (RTT150) at TBA degrees TAK National Observatory (TUG) and spectral data are taken with the Bok 2.3 m telescope on Kitt Peak, AZ.
Citation Formats
V. A. Acciari et al., “MULTIWAVELENGTH OBSERVATIONS OF LS I+61 degrees 303 WITH VERITAS, SWIFT, AND RXTE,” ASTROPHYSICAL JOURNAL, pp. 1034–1041, 2009, Accessed: 00, 2020. [Online]. Available: