2025ApJ...984....5L

Query : 2025ApJ...984....5L

2025ApJ...984....5L - Astrophys. J., 984, 5 (2025/May-1)

Detection of an Orphan X-Ray Flare from a Blazar Candidate EP240709a with the Einstein Probe.

LIU M., ZHANG Y., WANG Y., XUE R., BUCKLEY D., HOWELL D.A., JIN C., LI W., MONAGENG I., PAN H., SUN N.-C., TINYANONT S., WANG L., YUAN W., AN J., ANDREWS M., ANUTARAWIRAMKUL R., BUTPAN P., CHEN Y., CHENG H., CUI W., DAI C.-Y., DAI L., FARAH J., FENG H., FU S., GUO Z., JIA S., JIANG S., LI A., LI C., LI D., LIAN T., LIANG Y., LIU H., LIU X., LIU Y., MAO J., McCULLY C., NEWSOME M., PADILLA GONZALEZ E., PAN X., SUN X., TERRERAN G., WANG Z.-R., WU Q., XIAO H., XIONG D., XU D., XU X., XUE S., YANG H., YANG J., ZHANG J., ZHANG W., ZHANG W. and ZOU H.

Abstract (from CDS):

Blazars are often observed to flare across multiple wavelengths. Orphan flares from blazars have only been detected a few times, providing an opportunity to understand the structure of the jet in the accreting system. We report a remarkable orphan X-ray flare from a blazar candidate EP240709a, detected by the Einstein Probe (EP) in July 2024. The multiband spectral properties and variability support EP240709a as a high-energy peaked BL Lacertae-type object. The flux in 0.5-10 keV increased by at least 28 times to the value of low state in 2020, with no significant flaring detected in other bands during the same period. EP240709a exhibits the harder-when-brighter tendency in the X-ray band during the orphan flare, while its infrared-optical spectra are featureless. We employ one-zone and two-zone leptonic synchrotron self-Compton models to perform the spectral energy distribution fitting. Detecting this rare orphan flare shows the potential of EP in discovering peculiar activities from AGN in high-cadence X-ray sky surveys.

Abstract Copyright: © 2025. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Active galactic nuclei - Blazars - Jets - High energy astrophysics

Simbad objects: 7

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Number of rows : 7
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 SUMSS J003136-564637 BLL 00 31 35.4796812785 -56 46 41.469736929           ~ 13 0
2 8C 0716+714 BLL 07 21 53.4482942664 +71 20 36.363846516   15.5 15.50 14.27   ~ 1388 1
3 Z 184-50 BLL 11 04 27.3140835504 +38 12 31.798495872   13.50 12.90 8.31   ~ 2841 1
4 3C 279 Bla 12 56 11.16657958 -05 47 21.5251510   18.01 17.75 15.87   ~ 3205 2
5 1RXS J174357.3+193505 BLL 17 43 57.8330083440 +19 35 09.018846384     16.80 12.7   ~ 190 1
6 PKS J2009-4849 BLL 20 09 25.3903899240 -48 49 53.725051056   15.75 12.81 11.41   ~ 604 1
7 HD 224339 SB* 23 57 09.4947049080 -74 18 04.947832980   8.97 8.34     G0V 16 0

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