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out-of-TAC public ToO observations of ASASSN-18fv and MAXI J1820+070

26 April 2018 On 20 March a new bright transient optical source, near the Galactic plane, was found at V<10 by the All Sky Automated Survey for SuperNovae (ASAS-SN; ATel #11454). These observations showed an outburst amplitude of more than 7 mag. About a day later it was already brighter than 6 mag (see, e.g., AAVSO Alert Notice 626). Earlier spectroscopy (ATel #11456) had not ruled out a Galactic nova, but the transient might also be a large outburst of a young stellar object. Recently, Fermi/LAT and AGILE detected prolonged gamma-ray emission above ~100 MeV (ATels #11546, #11553). If the source is indeed a classical nova, one may expect nucleosynthesis line emission from the decay of 7Be at 478 keV. If this is the case, it makes ASASSN-18fv a very interesting target for INTEGRAL. This could finally give positive results regarding nucleosynthesis lines in novae, one of the objectives of INTEGRAL, and also help to understand the origin of the 7Be in the Galaxy (stellar component).

In view of the very recent detection with Fermi and AGILE and the potential of detecting 7Be line emission, ISOC received a ToO trigger to observe ASASSN-18fv as soon as possible. Although a TAC-approved ToO proposal on a new classical nova exists (PI: Hernanz), the nature of the source is still not 100% clear and the distance was not known yet at the time of the trigger. In consultation with the TAC and IUG it was, therefore, decided to start an out-of-TAC observation as soon as possible after the ToO trigger was received, i.e., from 23 April. The source continues to be very bright one month after discovery (V~6.8 mag; see, e.g., light curve at AAVSO), and it was, therefore, observed with the OMC in Fast monitoring mode. This is one of the few observations using this observing mode. There is a GAIA counterpart of the pre-nova source (G~19.4 mag). At the day of GAIA DR2, 25 April, it was reported that the distance is at least 1.6 kpc (most likely 6.6 kpc). Observations continue under the out-of-TAC proposal and remain publicly available, until further notice.

We will keep monitoring the recently discovered new black-hole X-ray binary transient MAXI J1820+070, aka ASASSN-18ey. The source became bright (up to 4 Crab in X-rays); this triggered an accepted INTEGRAL ToO proposal (PI: Belloni). Because the source is still bright, INTEGRAL keeps monitoring the source every Revolution, under an unsolicited, out-of-TAC program, until further notice. As a service to the community, especially meant to help multi-wavelength data comparisons, the ISDC is providing ready-to-use scientific data products of all available observations of the source in the form of light curves in 1 energy band for JEM-X1 (3–25 keV) and 2 energy bands for IBIS/ISGRI (25–60 and 60–200 keV). See ATel #11490.


18 April 2018 The deadline for the submission of proposals for AO-16 open time observations was on 13 April 2018, and all proposals are in the ISOC database. Below are some preliminary statistics on the proposals that have been received.

Total number of proposals
The total number of proposals received is 62. The total observing time requested is about 112 Msec (for all types of observation, i.e., fixed time, normal time, and ToO). Here, 10% of the requested total ToO time has been taken into account. Given that up to about 21 Msec of observing time (for new observing proposals) will be available for the AO-16 observing programme (12 months duration starting on 1 January 2019), this corresponds to an oversubscription in time by a factor of 5.3.

The non-ToO proposals are requesting data rights for 422 sources in total. 23 proposals requested coordinated time with NuSTAR, Swift and/or XMM-Newton.

Proposals per category
In the following table we give the breakdown of number of proposals as a function of the proposal category. Note that the numbers on requested observing times do include ToO proposals, but it has been assumed here, that a typical ToO proposal requests about 10% of its total observing time as entered into PGT from all the candidate sources included in a ToO proposal.

Scientific Category Number of proposals Requested observing time (Ms)
includes ToO times x 10%
Galactic Astronomy 32 50
Extragalactic Astronomy 18 16
Nucleosynthesis and diffuse
continuum/line emission
12 46
Total 62 112

End of May, the Time Allocation Committee will peer review all proposals and recommend the AO-16 observing programme to ESA.

INTEGRAL's operations indicatively extended up to end 2020

26 March 2018 Last week, ESA's Science Programme Committee (SPC) approved indicative extension for the operation of INTEGRAL by another year, i.e., until 31 December 2020. The decision will be subject to confirmation towards the end of 2018.

Donor Star breathes life into zombie companion

5 March 2018 INTEGRAL has witnessed a rare event: the moment that winds emitted by a swollen red giant star revived its slow-spinning companion, the core of a dead star, bringing it back to life in a flash of X-rays. The results have been published in Astronomy and Astrophysics. For more detail, please read the ESA Press Release.



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