SVOM detection of an X-ray flare from V* CC Eri
ATel #16958; F. Cangemi (APC, France), P. Maggi (ObAS, F), A. Coleiro (APC, F), D. Götz (CEA, F), J. Rodriguez (CEA, F), A. Foisseau (APC, F), S. Le Stum (APC, F), S. Schanne (CEA, F.) SVOM JSWG: J.-Y. Wei (NAOC, China), B. Cordier (CEA, F), Shuang-Nan Zhang (IHEP, C), S. Basa (LAM, F), O. Godet (IRAP, F), A. Claret (CEA, F), Z.-G. Dai (USTC, C), F. Daigne (IAP, F), J.-S. Deng (NAOC, C), A. Goldwurm (APC, F), X.-H. Han (NAOC, C), C. Lachaud (APC, F), E.-W. Liang (GXU, C), Y.-L. Qiu (NAOC, C), S. Vergani (Obs. Paris, F), J. Wang (NAOC, C), C. Wu (NAOC, F), L-.P. Xin (NAOC, C), B. Zhang (UNLV, C)
on 20 Dec 2024; 17:39 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Floriane Cangemi (cangemi@apc.in2p3.fr)
Subjects: X-ray, Star, Variables
On Sunday December 15th at 13:05:33 UTC (T0), the on-board trigger software of the SVOM/ECLAIRs telescope detected and localized a long duration soft X-ray transient at R.A., Dec = 38.703 deg, -43.899 deg (J2000). The source was detected by the image trigger (IMT) with a signal-to-noise ratio of 8.1 and an uncertainty radius of 9.75 arcmin in the 5-8 keV energy band during an 11 min time window beginning at 12:54:16.
After the automatic slew of the satellite, at 13:08:41 (i.e. 188 s after T0) the SVOM/MXT telescope (0.2-10 keV) detected a bright point source located 23 arcmin away from the catalogued source V* CC Eri â BY Dra. These observations hence suggest that V* CC Eri underwent a major X-ray flare.
A preliminary joint spectral analysis with SVOM/MXT (1.2 ks of exposure) and SVOM/ECLAIRs (1.9 ks of exposure) shows that the source is significantly detected up to ~30 keV. We fit the 0.4-50 keV spectrum with unabsorbed two APEC models with temperature of kT_1 = 1.9 (+0.4/-0.2) keV (90% confidence level) and kT_E = 0.91 +/- 0.06 keV respectively in addition with a cutoff powerlaw model with a photon index of Gamma = 0.9 +/- 0.1 and E_cut = 19.6 +/- 0.1 keV. The integrated 0.4-10 keV flux is about (1.2 +/- 0.4) e-9 erg/s/cm2 corresponding to a luminosity of 1.9e31 ergs/s for an assumed distance of 11.5 kpc.
V* CC Eri, an active binary star with star spots and flaring activity, and a prototype of BY Dra-type stars, offers a unique opportunity to study stellar magnetic processes, the evolution of stellar activity and their impact on exoplanetary environments.
The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. ECLAIRs was developed jointly by APC, CEA, CNES and IRAP. MXT has been developed jointly by CNES, CEA, IJCLab, University of Leicester and MPE.
