NICER observation list: Target ID 857901

Abstract

GRS 1915+105 is a black hole binary known for its unique variability, strong winds, jets, and BH spin. After 20+ years in outburst, NICER detected a huge change in this iconic source: the X-ray flux dropped by 100x! Spectra suggest a large obscuring shroud, but what is this obscuring gas? The 'obscured' state is highly variable, with flares that reveal strong winds and highly-ionized absorption. We propose to study its long-term evolution with 35 weekly exposures of 2.7 ks in Cycle 7. NICER is the only mission capable of frequently monitoring this important new state. We also request a 25 ks NuSTAR ToO to constrain scattering and wind photoionziation. These observations will continue to grow a NICER legacy archive of obscured variability in GRS 1915+105.
Obsid RA DEC l b Start End Exposure Number of
Modules		 Number of
Processing		 Status of
Processing		 Date of
Processing		 Public
date
8579010101 288.798 10.946 45.366 -0.219 60737.0088 60737.9769 5593.0 50 4 VALIDATED 60751.0 60751
8579010102 288.798 10.946 45.366 -0.219 60738.0374 60738.0414 293.0 50 3 VALIDATED 60751.1 60752
8579010201 288.797 10.945 45.364 -0.219 60743.5896 60743.9190 3586.0 50 5 VALIDATED 60753.7 60757
8579010301 288.798 10.943 45.363 -0.220 60750.2359 60750.5007 3109.0 50 6 VALIDATED 60760.5 60764
8579010401 288.799 10.946 45.366 -0.220 60758.5646 60758.7641 1897.0 50 6 VALIDATED 60769.8 60772
8579010501 288.798 10.946 45.366 -0.219 60763.0827 60763.6051 2378.0 50 4 VALIDATED 60774.9 60777
8579010601 288.798 10.946 45.366 -0.219 60771.1685 60771.9516 0.0 49 5 VALIDATED 60782.1 60785
8579010602 288.798 10.945 45.366 -0.220 60772.0127 60772.3389 0.0 50 6 VALIDATED 60787.1 60786
8579010701 288.799 10.946 45.366 -0.219 60778.5049 60778.9603 2585.0 50 4 VALIDATED 60788.4 60792
8579010702 288.798 10.947 45.366 -0.219 60779.0213 60779.0294 155.0 50 3 VALIDATED 60788.4 60793
8579010801 288.798 10.948 45.368 -0.218 60787.0875 60787.4812 1903.0 50 6 VALIDATED 60799.0 60801
8579011201 288.797 10.945 45.365 -0.218 60813.1854 60813.9620 2229.0 50 7 VALIDATED 60832.7 60827
8579011301 288.798 10.945 45.365 -0.219 60819.5595 60819.7584 2683.0 50 5 VALIDATED 60830.9 60833
8579011401 288.798 10.946 45.366 -0.219 60827.3029 60827.5669 3203.0 50 5 VALIDATED 60839.0 60841
8579011501 288.799 10.945 45.366 -0.220 60834.2127 60834.2972 1630.0 50 3 VALIDATED 60844.9 60848
8579011601 288.799 10.945 45.366 -0.220 60841.0558 60841.1454 634.0 50 6 VALIDATED 60864.5 60855