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INTEGRAL observations of SRGA J043520.9+552226In the spring of this year SRG/ART-XC detected a new hard X-ray transient SRGA J043520.9+552226 associated with a slowly varying optical transient AT2019wey. A week days ago SRG observed this source for the second time in the course of its all-sky survey and found it to be even brighter at a flux of ~5e-10 ergs/cm2/s.During the April-September this source was extensively monitored by different X-ray (Swift/NICER/NuSTAR/Chandra) observatories along with optical and radio observations. There are different clues that indicate that the SRGA J043520.9+552226 is an accreting XB in our Galaxy.Three NuSTAR observations made after our discovery shown that the source spectrum is hard with powerlaw slope of 1.8-2 and no obvious cut-off at high energies. Two of these observations happened in the late August the 30-60 keV flux was about 40 mCrab.We are planning to utilize a break from all-sky survey on Oct 5 caused by a correction of the SRG orbit in order to perform anobservation of this source. Currently we have scheduled this observation to happen on 2020-10-05 20:40:00 - 2020-10-06 00:00:00 UTC but we will try to expand it. We are asking INTEGRAL to join this observation pursuing two main tasks: first we would like to obtain a set of simultaneous observations with ART-XC JEM-X and IBIS in order to perform cross-calibration second we would like to use INTEGRAL data to measure the spectral shape at high energies (above 80 keV). [truncated! Please see actual data for full text]

INTEGRAL（国际伽马射线天体物理实验室）对SRGA J043520.9+552226的观测记录

今年春季，SRG/ART-XC探测到一例新的硬X射线暂变源（hard X-ray transient）SRGA J043520.9+552226，该源与光学暂现源（optical transient）AT2019wey成协。一周前，SRG在其全天空巡天（all-sky survey）过程中对该源进行第二次观测，发现其亮度进一步提升，通量约为5×10^-10 尔格/(平方厘米·秒)。

今年4月至9月期间，包括斯威夫特（Swift）、NICER、努斯塔（NuSTAR）、钱德拉（Chandra）在内的多台X射线天文台，搭配光学与射电观测设备，对该源开展了全面监测。多项线索表明，SRGA J043520.9+552226是银河系内的一颗吸积X射线双星（accreting X-ray binary, XB）。

我们在发现该源后开展的三次NuSTAR观测结果显示，其光谱偏硬，幂律斜率（powerlaw slope）为1.8~2，且高能段无明显截断（cut-off）。其中两次观测于8月下旬进行，该源在30~60 keV能段的通量约为40毫蟹状星云通量（millicrab, mCrab）。

我们计划利用10月5日因SRG轨道修正而空出的全天空巡天间隙开展此次源观测，目前已将观测时段安排为协调世界时2020年10月5日20:40:00至2020年10月6日00:00:00，并尝试延长观测时长。我们诚邀INTEGRAL参与此次观测，主要达成两项科学目标：其一，与ART-XC的JEM-X和IBIS探测器开展同步观测（simultaneous observations），以完成交叉定标（cross-calibration）；其二，利用INTEGRAL的观测数据测量80 keV以上高能段的光谱形态。

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