NICER observation list: Target ID 263601


Understanding the corona and disk-coronal interaction is a forefront challenge in black hole systems. While NuSTAR is the leading instrument at probing the high-energy spectral reflection component, NICER provides a complementary view of the thermal accretion disk. Both components are very strong for Cyg X-1, but the disk is cool and out of reach for NuSTAR alone. This proposal is a continuation of a previously approved NuSTAR Cycle 3 program on Cyg X-1 using the uniquely powerful capability of combined continuum and reflection modeling provided with both instruments together. By chance, our first program covered the soft state only. We propose to expand and target hard states and request 3x20 ks NuSTAR (3x4 ks NICER) observations of Cyg X-1 for triggered monitoring of hard states.
Obsid RA DEC l b Start End Exposure Number of
Number of
Status of
Date of
2636010101 299.590 35.202 71.335 3.067 58701.3759 58701.9117 14156.0 52 2 VALIDATED 58705.7 59075
2636010102 299.591 35.201 71.335 3.066 58800.4389 58800.9016 13039.0 52 2 VALIDATED 58805.7 59174
2636010201 299.590 35.202 71.335 3.067 58744.9882 58745.3873 4209.0 52 3 VALIDATED 58750.6 59119