The X-ray bursts within the 2010 outburst of the accreting millisecond X-ray pulsar SAX J1748.9-2021

被引:1
作者
Wu, Ziwei [1 ,2 ]
Ding, Guoqiang [1 ]
Li, Zhibing [1 ]
Chen, Yupeng [3 ]
Qu, Jinlu [3 ]
机构
[1] Chinese Acad Sci, Xinjiang Astron Observ, 150,Sci 1 St, Urumqi 830011, Xinjiang, Peoples R China
[2] Univ Chinese Acad Sci, Beijing 100049, Peoples R China
[3] Chinese Acad Sci, Inst High Energy Phys, Key Lab Particle Astrophys, Beijing 100049, Peoples R China
关键词
Stars: neutron; X-rays: bursts; Individual (SAX J1748.9-2021); GLOBULAR-CLUSTER NGC-6440; PHOTOSPHERIC RADIUS EXPANSION; NEUTRON-STAR; MASS; DISCOVERY; TRANSIENT; RATES; PULSATIONS; EVOLUTION; EMISSION;
D O I
10.1007/s10509-018-3367-1
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
With the observations from Rossi X-ray Timing Explorer, we search and study the X-ray bursts of accreting millisecond X-ray pulsar SAX J1748.9-2021 during its 2010 outburst. We find 13 X-ray bursts, including 12 standard type-I X-ray bursts and an irregular X-ray burst which lacks cooling tail. During the outburst, the persistent emission occurred at . We use a combination model of a blackbody (BB), a powerlaw, and a line component to fit the persistent emission spectra. Another BB is added into the combination model to account for the emission of the X-ray bursts due to the thermonuclear burning on the surface of the neutron star. Finally, we modify the combination model with a multiplicative factor , plus a BB to fit the spectra during the X-ray bursts. It is found that the is inversely correlated with the burst flux in some cases. Our analysis suggests that the ignition depth of the irregular X-ray burst is obviously smaller than those of the type-I X-ray bursts. We argue that the detected type-I X-ray bursts originate from helium-rich or pure-helium environment, while the irregular X-ray burst originates from the thermonuclear flash in a shallow ocean.
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页数:10
相关论文
共 59 条
[1]   Intermittent millisecond X-ray pulsations from the neutron star X-ray transient SAX J1748.9-2021 in the globular cluster NGC 6440 [J].
Altamirano, D. ;
Casella, P. ;
Patruno, A. ;
Wijnands, R. ;
van der Klis, M. .
ASTROPHYSICAL JOURNAL LETTERS, 2008, 674 (01) :L45-L48
[2]  
[Anonymous], 2006, CAMBRIDGE ASTROPHYSI
[3]  
Arnaud KA, 1996, ASTR SOC P, V101, P17
[4]   NuSTAR OBSERVATION OF A TYPE I X-RAY BURST FROM GRS 1741.9-2853 [J].
Barriere, Nicolas M. ;
Krivonos, Roman ;
Tomsick, John A. ;
Bachetti, Matteo ;
Boggs, Steven E. ;
Chakrabarty, Deepto ;
Christensen, Finn E. ;
Craig, William W. ;
Hailey, Charles J. ;
Harrison, Fiona A. ;
Hong, Jaesub ;
Mori, Kaya ;
Stern, Daniel ;
Zhang, William W. .
ASTROPHYSICAL JOURNAL, 2015, 799 (02)
[5]   DISCOVERY OF X-RAY BURSTS FROM A REGION IN CONSTELLATION NORMA [J].
BELIAN, RD ;
CONNER, JP ;
EVANS, WD .
ASTROPHYSICAL JOURNAL, 1976, 206 (03) :L135-L138
[6]  
Bozzo E., 2015, Astron. Telegram, V7106, P1
[7]   The Optical Counterpart to the Accreting Millisecond X-Ray Pulsar SAX J1748.9-2021 in the Globular Cluster NGC 6440 [J].
Cadelano, M. ;
Pallanca, C. ;
Ferraro, F. R. ;
Dalessandro, E. ;
Lanzoni, B. ;
Patruno, A. .
ASTROPHYSICAL JOURNAL, 2017, 844 (01)
[8]   Type-I bursts within outbursts of IGR J17473-2721 [J].
Chen, Y. -P. ;
Zhang, S. ;
Torres, D. F. ;
Wang, J. -M. ;
Li, T. -P. .
ASTRONOMY & ASTROPHYSICS, 2010, 510
[9]   On the physics of type I X-ray bursts on accreting neutron stars at high accretion rates [J].
Cooper, Randall L. ;
Narayan, Ramesh .
ASTROPHYSICAL JOURNAL, 2006, 648 (02) :L123-L126
[10]   Rotational evolution during Type I X-ray bursts [J].
Cumming, A ;
Bildsten, L .
ASTROPHYSICAL JOURNAL, 2000, 544 (01) :453-474