Co-authors: G. Belanger, ESA-ESAC, Spain V. Burwitz, MPI for Extraterrestrial Physics, Germany K.... more Co-authors: G. Belanger, ESA-ESAC, Spain V. Burwitz, MPI for Extraterrestrial Physics, Germany K. Forster, California Institute of Technology, USA C. E. Grant, MIT Kavli Institute for Astrophysics and Space Research M. Guainazzi, ESA-ESTEC, The Netherlands V. L. Kashyap, Center for Astrophysics | Harvard & Smithsonian, USA H. L. Marshall, MIT Kavli Institute for Astrophysics and Space Research, USA E. D. Miller, MIT Kavli Institute for Astrophysics and Space Research, USA L. Natalucci, IAPS-INAF, Italy P. P. Plucinsky, Center for Astrophysics | Harvard & Smithsonian, USA Y. Terada, Saitama University/Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Japan
ABSTRACT One of the primary science objectives of the NASA SMEX hard X-ray mission NuSTAR is to c... more ABSTRACT One of the primary science objectives of the NASA SMEX hard X-ray mission NuSTAR is to conduct extragalactic and Galactic surveys in the 5 - 80 keV hard X-ray band. With its improved sensitivity over previous satellites at energies above 10 keV, NuSTAR will study populations of these energies, facilitating the& ulti-wavelength identification of high-energy sources, as well as uncovering hidden populations. NuSIM is the instrument and science simulator for NuSTAR. It utilizes a completely object-oriented design based on C++ and ROOT in order to encapsulate individual simulation tasks in independent modules. The simulation modules encompass all relevant aspects of NuSTAR which are required to predict, plan, and compare measurements with simulations. These modules include astrophysical sources models, the optics system, a detailed detector interaction and detector effects engine, a trigger and data packaging engine, a data calibrator, as well as models for the mast movement, the star tracker, and the metrology system. We provide a short overview of NuSIM's key design features related to the surveying mode of the observatory, and show simulations of the Galactic center and the COSMOS field.
By characterizing the contribution of stray light to large data sets from the CXB Measurement X-r... more By characterizing the contribution of stray light to large data sets from the CXB Measurement X-ray observatory collected over 2012–2017, we report a measurement of the cosmic X-ray background (CXB) in the 3–20 keV energy range. These data represent ∼20% sky coverage while avoiding Galactic ridge X-ray emission and are less weighted by deep survey fields than previous measurements with CXB Measurement. Images in narrow energy bands are stacked in detector space and spatially fit with a model representing the stray light and uniform pattern expected from the CXB and the instrumental background, respectively. We establish baseline flux values from Earth-occulted data and validate the fitting method on stray-light observations of the Crab, which further serve to calibrate the resulting spectra. We present independent spectra of the CXB with the focal plane module FPMA and FPMB detector arrays, which are in excellent agreement with the canonical characterization by HEAO 1 and are 10% lower than most subsequent measurements: F 3 − 20 keV FPMA = 2.63 × 10 − 11 erg s − 1 cm − 2 deg − 2 and F 3 – 20 keV FPMB = 2.58 × 10 − 11 erg s − 1 cm − 2 deg − 2 . We discuss these results in light of previous measurements of the CXB and consider the impact of systematic uncertainties on our spectra.
ABSTRACT We propose to obtain complete 2-band Spitzer/IRAC maps over the entire NuSTAR field-of-v... more ABSTRACT We propose to obtain complete 2-band Spitzer/IRAC maps over the entire NuSTAR field-of-view for all non-survey fields observed during the 2-year primary NuSTAR mission. Such data are important for identifying the low-energy counterparts to NuSTAR sources, which is a prerequisite for follow-up spectroscopy and fully characterizing the NuSTAR sources. The proposed 134.4 hr program will vastly improve our understanding of the sources responsible for the peak of the cosmic X-ray background, which is poorly understood currently -- only 1-2% of the X-ray background is resolved at 20-30 keV by missions prior to NUSTAR. The proposed data will also provide an important multi-mission NASA data base, including high-energy (3-79 keV) NuSTAR observations, low-energy (0.2-10 keV) Swift/XRT observations, and mid-infrared Spitzer/IRAC data. These data will be useful for stacking analyses, as well as provide a valuable legacy data set to the community.
Co-authors: G. Belanger, ESA-ESAC, Spain V. Burwitz, MPI for Extraterrestrial Physics, Germany K.... more Co-authors: G. Belanger, ESA-ESAC, Spain V. Burwitz, MPI for Extraterrestrial Physics, Germany K. Forster, California Institute of Technology, USA C. E. Grant, MIT Kavli Institute for Astrophysics and Space Research M. Guainazzi, ESA-ESTEC, The Netherlands V. L. Kashyap, Center for Astrophysics | Harvard & Smithsonian, USA H. L. Marshall, MIT Kavli Institute for Astrophysics and Space Research, USA E. D. Miller, MIT Kavli Institute for Astrophysics and Space Research, USA L. Natalucci, IAPS-INAF, Italy P. P. Plucinsky, Center for Astrophysics | Harvard & Smithsonian, USA Y. Terada, Saitama University/Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Japan
ABSTRACT One of the primary science objectives of the NASA SMEX hard X-ray mission NuSTAR is to c... more ABSTRACT One of the primary science objectives of the NASA SMEX hard X-ray mission NuSTAR is to conduct extragalactic and Galactic surveys in the 5 - 80 keV hard X-ray band. With its improved sensitivity over previous satellites at energies above 10 keV, NuSTAR will study populations of these energies, facilitating the& ulti-wavelength identification of high-energy sources, as well as uncovering hidden populations. NuSIM is the instrument and science simulator for NuSTAR. It utilizes a completely object-oriented design based on C++ and ROOT in order to encapsulate individual simulation tasks in independent modules. The simulation modules encompass all relevant aspects of NuSTAR which are required to predict, plan, and compare measurements with simulations. These modules include astrophysical sources models, the optics system, a detailed detector interaction and detector effects engine, a trigger and data packaging engine, a data calibrator, as well as models for the mast movement, the star tracker, and the metrology system. We provide a short overview of NuSIM's key design features related to the surveying mode of the observatory, and show simulations of the Galactic center and the COSMOS field.
By characterizing the contribution of stray light to large data sets from the CXB Measurement X-r... more By characterizing the contribution of stray light to large data sets from the CXB Measurement X-ray observatory collected over 2012–2017, we report a measurement of the cosmic X-ray background (CXB) in the 3–20 keV energy range. These data represent ∼20% sky coverage while avoiding Galactic ridge X-ray emission and are less weighted by deep survey fields than previous measurements with CXB Measurement. Images in narrow energy bands are stacked in detector space and spatially fit with a model representing the stray light and uniform pattern expected from the CXB and the instrumental background, respectively. We establish baseline flux values from Earth-occulted data and validate the fitting method on stray-light observations of the Crab, which further serve to calibrate the resulting spectra. We present independent spectra of the CXB with the focal plane module FPMA and FPMB detector arrays, which are in excellent agreement with the canonical characterization by HEAO 1 and are 10% lower than most subsequent measurements: F 3 − 20 keV FPMA = 2.63 × 10 − 11 erg s − 1 cm − 2 deg − 2 and F 3 – 20 keV FPMB = 2.58 × 10 − 11 erg s − 1 cm − 2 deg − 2 . We discuss these results in light of previous measurements of the CXB and consider the impact of systematic uncertainties on our spectra.
ABSTRACT We propose to obtain complete 2-band Spitzer/IRAC maps over the entire NuSTAR field-of-v... more ABSTRACT We propose to obtain complete 2-band Spitzer/IRAC maps over the entire NuSTAR field-of-view for all non-survey fields observed during the 2-year primary NuSTAR mission. Such data are important for identifying the low-energy counterparts to NuSTAR sources, which is a prerequisite for follow-up spectroscopy and fully characterizing the NuSTAR sources. The proposed 134.4 hr program will vastly improve our understanding of the sources responsible for the peak of the cosmic X-ray background, which is poorly understood currently -- only 1-2% of the X-ray background is resolved at 20-30 keV by missions prior to NUSTAR. The proposed data will also provide an important multi-mission NASA data base, including high-energy (3-79 keV) NuSTAR observations, low-energy (0.2-10 keV) Swift/XRT observations, and mid-infrared Spitzer/IRAC data. These data will be useful for stacking analyses, as well as provide a valuable legacy data set to the community.
Uploads
Papers