TY  - JOUR
A1  - Bozzo, Enrico
A1  - Bernardini, F.
A1  - Ferrigno, Carlo
A1  - Falanga, M.
A1  - Romano, Patrizia
A1  - Oskinova, Lida
T1  - The accretion environment of supergiant fast X-ray transients probed with XMM-Newton
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Context. Supergiant fast X-ray (SFXT) transients are a peculiar class of supergiant X-ray binaries characterized by a remarkable variability in the X-ray domain, widely ascribed to accretion from a clumpy stellar wind. Aims. In this paper we performed a systematic and homogeneous analysis of the sufficiently bright X-ray flares observed with XMM-Newton from the supergiant fast X-ray transients to probe spectral variations on timescales as short as a few hundred seconds. Our ultimate goal is to investigate whether SFXT flares and outbursts are triggered by the presence of clumps, and to reveal whether strongly or mildly dense clumps are required. Methods. For all sources, we employ a technique developed by our group already exploited in a number of our previous papers, making use of an adaptive rebinned hardness ratio to optimally select the time intervals for the spectral extraction. A total of twelve observations performed in the direction of five SFXTs are reported, providing the largest sample of events available so far. Results. Using the original results reported here and those obtained with our technique from the analysis of two previously published XMM-Newton observations of IGR J17544-2619 and IGR J18410-0535, we show that both strongly and mildly dense clumps can trigger these events. In the former case, the local absorption column density may increase by a factor of >> 3, while in the latter case, the increase is only a factor of similar to 2-3 (or lower). An increase in the absorption column density is generally recorded during the rise of the flares/outbursts, while a drop follows when the source achieves peak flux. In a few cases, a re-increase of the absorption column density after the flare is also detected, and we discovered one absorption event related to the passage of an unaccreted clump in front of the compact object. Overall, there seems to be no obvious correlation between the dynamic ranges in the X-ray fluxes and absorption column densities in supergiant fast X-ray transients, with an indication that lower densities are recorded at the highest fluxes. Conclusions. The spectral variations measured in all sources are in agreement with the idea that the flares/outbursts are triggered by the presence of dense structures in the wind interacting with the X-rays from the compact object (leading to photoionization). The lack of correlation between the dynamic ranges in the X-ray fluxes and absorption column densities can be explained by the presence of accretion inhibition mechanism(s). Based on the knowledge acquired so far on the SFXTs, we propose a classification of the flares/outbursts from these sources in order to drive future observational investigations. We suggest that the difference between the classes of flares/outbursts is related to the fact that the mechanism(s) inhibiting accretion can be overcome more easily in some sources compared to others. We also investigate the possibility that different stellar wind structures, other than clumps, could provide the means to temporarily overcome the inhibition of accretion in supergiant fast X-ray transients.
KW  - X-rays: individuals: IGRJ18450-0435
KW  - X-rays: individuals: IGRJ17544-2619
KW  - X-rays: binaries
KW  - X-rays: individuals: SAXJ1818.6-1703
KW  - X-rays: individuals: IGRJ17354-3255
KW  - X-rays: individuals: IGRJ16328-4726
Y1  - 2017
U6  - https://doi.org/10.1051/0004-6361/201730398
SN  - 1432-0746
VL  - 608
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Acero, F.
A1  - Aloisio, R.
A1  - Amans, J.
A1  - Amato, Elena
A1  - Antonelli, L. A.
A1  - Aramo, C.
A1  - Armstrong, T.
A1  - Arqueros, F.
A1  - Asano, Katsuaki
A1  - Ashley, M.
A1  - Backes, M.
A1  - Balazs, C.
A1  - Balzer, A.
A1  - Bamba, Aya
A1  - Barkov, Maxim
A1  - Barrio, J. A.
A1  - Benbow, Wystan
A1  - Bernloehr, K.
A1  - Beshley, V.
A1  - Bigongiari, C.
A1  - Biland, A.
A1  - Bilinsky, A.
A1  - Bissaldi, Elisabetta
A1  - Biteau, J.
A1  - Blanch, O.
A1  - Blasi, P.
A1  - Blazek, J.
A1  - Boisson, C.
A1  - Bonanno, G.
A1  - Bonardi, A.
A1  - Bonavolonta, C.
A1  - Bonnoli, G.
A1  - Braiding, C.
A1  - Brau-Nogue, S.
A1  - Bregeon, J.
A1  - Brown, A. M.
A1  - Bugaev, V.
A1  - Bulgarelli, A.
A1  - Bulik, T.
A1  - Burton, Michael
A1  - Burtovoi, A.
A1  - Busetto, G.
A1  - Bottcher, M.
A1  - Cameron, R.
A1  - Capalbi, M.
A1  - Caproni, Anderson
A1  - Caraveo, P.
A1  - Carosi, R.
A1  - Cascone, E.
A1  - Cerruti, M.
A1  - Chaty, Sylvain
A1  - Chen, A.
A1  - Chen, X.
A1  - Chernyakova, M.
A1  - Chikawa, M.
A1  - Chudoba, J.
A1  - Cohen-Tanugi, J.
A1  - Colafrancesco, S.
A1  - Conforti, V.
A1  - Contreras, J. L.
A1  - Costa, A.
A1  - Cotter, G.
A1  - Covino, Stefano
A1  - Covone, G.
A1  - Cumani, P.
A1  - Cusumano, G.
A1  - Daniel, M.
A1  - Dazzi, F.
A1  - De Angelis, A.
A1  - De Cesare, G.
A1  - De Franco, A.
A1  - De Frondat, F.
A1  - Dal Pino, E. M. de Gouveia
A1  - De Lisio, C.
A1  - Lopez, R. de los Reyes
A1  - De Lotto, B.
A1  - de Naurois, M.
A1  - De Palma, F.
A1  - Del Santo, M.
A1  - Delgado, C.
A1  - della Volpe, D.
A1  - Di Girolamo, T.
A1  - Di Giulio, C.
A1  - Di Pierro, F.
A1  - Di Venere, L.
A1  - Doro, M.
A1  - Dournaux, J.
A1  - Dumas, D.
A1  - Dwarkadas, Vikram V.
A1  - Diaz, C.
A1  - Ebr, J.
A1  - Egberts, Kathrin
A1  - Einecke, S.
A1  - Elsaesser, D.
A1  - Eschbach, S.
A1  - Falceta-Goncalves, D.
A1  - Fasola, G.
A1  - Fedorova, E.
A1  - Fernandez-Barral, A.
A1  - Ferrand, Gilles
A1  - Fesquet, M.
A1  - Fiandrini, E.
A1  - Fiasson, A.
A1  - Filipovic, Miroslav D.
A1  - Fioretti, V.
A1  - Font, L.
A1  - Fontaine, Gilles
A1  - Franco, F. J.
A1  - Freixas Coromina, L.
A1  - Fujita, Yutaka
A1  - Fukui, Y.
A1  - Funk, S.
A1  - Forster, A.
A1  - Gadola, A.
A1  - Lopez, R. Garcia
A1  - Garczarczyk, M.
A1  - Giglietto, N.
A1  - Giordano, F.
A1  - Giuliani, A.
A1  - Glicenstein, J.
A1  - Gnatyk, R.
A1  - Goldoni, P.
A1  - Grabarczyk, T.
A1  - Graciani, R.
A1  - Graham, J.
A1  - Grandi, P.
A1  - Granot, Jonathan
A1  - Green, A. J.
A1  - Griffiths, S.
A1  - Gunji, S.
A1  - Hakobyan, H.
A1  - Hara, S.
A1  - Hassan, T.
A1  - Hayashida, M.
A1  - Heller, M.
A1  - Helo, J. C.
A1  - Hinton, J.
A1  - Hnatyk, B.
A1  - Huet, J.
A1  - Huetten, M.
A1  - Humensky, T. B.
A1  - Hussein, M.
A1  - Horandel, J.
A1  - Ikeno, Y.
A1  - Inada, T.
A1  - Inome, Y.
A1  - Inoue, S.
A1  - Inoue, T.
A1  - Inoue, Y.
A1  - Ioka, K.
A1  - Iori, Maurizio
A1  - Jacquemier, J.
A1  - Janecek, P.
A1  - Jankowsky, D.
A1  - Jung, I.
A1  - Kaaret, P.
A1  - Katagiri, H.
A1  - Kimeswenger, S.
A1  - Kimura, Shigeo S.
A1  - Knodlseder, J.
A1  - Koch, B.
A1  - Kocot, J.
A1  - Kohri, K.
A1  - Komin, N.
A1  - Konno, Y.
A1  - Kosack, K.
A1  - Koyama, S.
A1  - Kraus, Michaela
A1  - Kubo, Hidetoshi
A1  - Mezek, G. Kukec
A1  - Kushida, J.
A1  - La Palombara, N.
A1  - Lalik, K.
A1  - Lamanna, G.
A1  - Landt, H.
A1  - Lapington, J.
A1  - Laporte, P.
A1  - Lee, S.
A1  - Lees, J.
A1  - Lefaucheur, J.
A1  - Lenain, J. -P.
A1  - Leto, Giuseppe
A1  - Lindfors, E.
A1  - Lohse, T.
A1  - Lombardi, S.
A1  - Longo, F.
A1  - Lopez, M.
A1  - Lucarelli, F.
A1  - Luque-Escamilla, Pedro Luis
A1  - Lopez-Coto, R.
A1  - Maccarone, M. C.
A1  - Maier, G.
A1  - Malaguti, G.
A1  - Mandat, D.
A1  - Maneva, G.
A1  - Mangano, S.
A1  - Marcowith, Alexandre
A1  - Marti, J.
A1  - Martinez, M.
A1  - Martinez, G.
A1  - Masuda, S.
A1  - Maurin, G.
A1  - Maxted, N.
A1  - Melioli, Claudio
A1  - Mineo, T.
A1  - Mirabal, N.
A1  - Mizuno, T.
A1  - Moderski, R.
A1  - Mohammed, M.
A1  - Montaruli, T.
A1  - Moralejo, A.
A1  - Mori, K.
A1  - Morlino, G.
A1  - Morselli, A.
A1  - Moulin, Emmanuel
A1  - Mukherjee, R.
A1  - Mundell, C.
A1  - Muraishi, H.
A1  - Murase, Kohta
A1  - Nagataki, Shigehiro
A1  - Nagayoshi, T.
A1  - Naito, T.
A1  - Nakajima, D.
A1  - Nakamori, T.
A1  - Nemmen, R.
A1  - Niemiec, Jacek
A1  - Nieto, D.
A1  - Nievas-Rosillo, M.
A1  - Nikolajuk, M.
A1  - Nishijima, K.
A1  - Noda, K.
A1  - Nogues, L.
A1  - Nosek, D.
A1  - Novosyadlyj, B.
A1  - Nozaki, S.
A1  - Ohira, Yutaka
A1  - Ohishi, M.
A1  - Ohm, S.
A1  - Okumura, A.
A1  - Ong, R. A.
A1  - Orito, R.
A1  - Orlati, A.
A1  - Ostrowski, M.
A1  - Oya, I.
A1  - Padovani, Marco
A1  - Palacio, J.
A1  - Palatka, M.
A1  - Paredes, Josep M.
A1  - Pavy, S.
A1  - Persic, M.
A1  - Petrucci, P.
A1  - Petruk, Oleh
A1  - Pisarski, A.
A1  - Pohl, Martin
A1  - Porcelli, A.
A1  - Prandini, E.
A1  - Prast, J.
A1  - Principe, G.
A1  - Prouza, M.
A1  - Pueschel, Elisa
A1  - Puelhofer, G.
A1  - Quirrenbach, A.
A1  - Rameez, M.
A1  - Reimer, O.
A1  - Renaud, M.
A1  - Ribo, M.
A1  - Rico, J.
A1  - Rizi, V.
A1  - Rodriguez, J.
A1  - Fernandez, G. Rodriguez
A1  - Rodriguez Vazquez, J. J.
A1  - Romano, Patrizia
A1  - Romeo, G.
A1  - Rosado, J.
A1  - Rousselle, J.
A1  - Rowell, G.
A1  - Rudak, B.
A1  - Sadeh, I.
A1  - Safi-Harb, S.
A1  - Saito, T.
A1  - Sakaki, N.
A1  - Sanchez, D.
A1  - Sangiorgi, P.
A1  - Sano, H.
A1  - Santander, M.
A1  - Sarkar, S.
A1  - Sawada, M.
A1  - Schioppa, E. J.
A1  - Schoorlemmer, H.
A1  - Schovanek, P.
A1  - Schussler, F.
A1  - Sergijenko, O.
A1  - Servillat, M.
A1  - Shalchi, A.
A1  - Shellard, R. C.
A1  - Siejkowski, H.
A1  - Sillanpaa, A.
A1  - Simone, D.
A1  - Sliusar, V.
A1  - Sol, H.
A1  - Stanic, S.
A1  - Starling, R.
A1  - Stawarz, L.
A1  - Stefanik, S.
A1  - Stephan, M.
A1  - Stolarczyk, T.
A1  - Szanecki, M.
A1  - Szepieniec, T.
A1  - Tagliaferri, G.
A1  - Tajima, H.
A1  - Takahashi, M.
A1  - Takeda, J.
A1  - Tanaka, M.
A1  - Tanaka, S.
A1  - Tejedor, L. A.
A1  - Telezhinsky, Igor O.
A1  - Temnikov, P.
A1  - Terada, Y.
A1  - Tescaro, D.
A1  - Teshima, M.
A1  - Testa, V.
A1  - Thoudam, S.
A1  - Tokanai, F.
A1  - Torres, D. F.
A1  - Torresi, E.
A1  - Tosti, G.
A1  - Townsley, C.
A1  - Travnicek, P.
A1  - Trichard, C.
A1  - Trifoglio, M.
A1  - Tsujimoto, S.
A1  - Vagelli, V.
A1  - Vallania, P.
A1  - Valore, L.
A1  - van Driel, W.
A1  - van Eldik, C.
A1  - Vandenbroucke, Justin
A1  - Vassiliev, V.
A1  - Vecchi, M.
A1  - Vercellone, Stefano
A1  - Vergani, S.
A1  - Vigorito, C.
A1  - Vorobiov, S.
A1  - Vrastil, M.
A1  - Vazquez Acosta, M. L.
A1  - Wagner, S. J.
A1  - Wagner, R.
A1  - Wakely, S. P.
A1  - Walter, R.
A1  - Ward, J. E.
A1  - Watson, J. J.
A1  - Weinstein, A.
A1  - White, M.
A1  - White, R.
A1  - Wierzcholska, A.
A1  - Wilcox, P.
A1  - Williams, D. A.
A1  - Wischnewski, R.
A1  - Wojcik, P.
A1  - Yamamoto, T.
A1  - Yamamoto, H.
A1  - Yamazaki, Ryo
A1  - Yanagita, S.
A1  - Yang, L.
A1  - Yoshida, T.
A1  - Yoshida, M.
A1  - Yoshiike, S.
A1  - Yoshikoshi, T.
A1  - Zacharias, M.
A1  - Zampieri, L.
A1  - Zanin, R.
A1  - Zavrtanik, M.
A1  - Zavrtanik, D.
A1  - Zdziarski, A.
A1  - Zech, Alraune
A1  - Zechlin, Hannes
A1  - Zhdanov, V.
A1  - Ziegler, A.
A1  - Zorn, J.
T1  - Prospects for Cherenkov Telescope Array Observations of the Young Supernova Remnant RX J1713.7-3946
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We perform simulations for future Cherenkov Telescope Array (CTA) observations of RX J1713.7-3946, a young supernova remnant (SNR) and one of the brightest sources ever discovered in very high energy (VHE) gamma rays. Special attention is paid to exploring possible spatial (anti) correlations of gamma rays with emission at other wavelengths, in particular X-rays and CO/H I emission. We present a series of simulated images of RX J1713.7-3946 for CTA based on a set of observationally motivated models for the gamma-ray emission. In these models, VHE gamma rays produced by high-energy electrons are assumed to trace the nonthermal X-ray emission observed by XMM-Newton, whereas those originating from relativistic protons delineate the local gas distributions. The local atomic and molecular gas distributions are deduced by the NANTEN team from CO and H I observations. Our primary goal is to show how one can distinguish the emission mechanism(s) of the gamma rays (i.e., hadronic versus leptonic, or a mixture of the two) through information provided by their spatial distribution, spectra, and time variation. This work is the first attempt to quantitatively evaluate the capabilities of CTA to achieve various proposed scientific goals by observing this important cosmic particle accelerator.
KW  - cosmic rays
KW  - gamma rays: ISM
KW  - ISM: individual objects (RX J1713.7-3946, G347.3-0.5)
Y1  - 2017
U6  - https://doi.org/10.3847/1538-4357/aa6d67
SN  - 0004-637X
SN  - 1538-4357
VL  - 840
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -