Amendment 23: D.5 Swift General Investigator Amendment: IXPE Joint Observing Program and Change to NuSTAR Exclusive-Use Period.

D.5 Neil Gehrels Swift Observatory General Investigator (GI) - Cycle 21 solicits proposals for basic research relevant to the Swift gamma-ray burst mission. The primary goal of this mission is to determine the origin of gamma-ray bursts (GRBs) and use these bursts to probe the early Universe. Two changes have been made to D.5 Swift GI: 1) A joint GI observing program with Imaging X-ray Polarimetry Explorer has been added and 2) all NuSTAR data acquired through the Swift GI Program will have a standard 6-month exclusive-use period, see Section 1.3.2. New text is in bold and deleted text is struck through. The proposal due date is unchanged: Phase-1 proposals are due by 4:30 p.m. Eastern time on September 26, 2024, via ARK/RPS.

On or about June 24, 2024, this Amendment to the NASA Research Announcement "Research Opportunities in Space and Earth Sciences (ROSES) 2024" (NNH24ZDA001N) will be posted on the NASA research opportunity homepage at https://solicitation.nasaprs.com/ROSES2024 and will appear on SARA's ROSES blog at: https://science.nasa.gov/researchers/solicitations/roses-2024/

Programmatic information concerning D.5 Swift GI may be obtained from Mario Perez at mario.perez@nasa.gov and Technical questions concerning this program element may be directed to Bindu Rani at bindu.rani@nasa.gov.