Soft Gamma-Ray Polarimetry with COSI Using Maximum Likelihood Analysis

Tomsick, John A.; Lowell, A.; Lazar, Hadar; Sleator, Clio; Zoglauer, Andreas

doi:10.1007/978-981-16-4544-0_145-1

Cited by 11 publications

(16 citation statements)

References 35 publications

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“…Differences in evolutionary paths of BAT and LAT blazars have been already reported in previous works (A09; A12; A14; Toda et al 2020), and possibly a combined LAT-BAT-detected blazar luminosity function study is due. Alternatively, an allsky MeV instrument (e.g., COSI; Tomsick et al 2019;AMEGO-X;Caputo et al 2022; see Section 8.5) would enable us to produce new measurements of the background in the MeV energy range, to pinpoint the peak of the SED of these powerful blazars, and to understand what type of evolutionary scenario is taking place in this source class.…”

Section: Mev Versus Gev Blazarsmentioning

confidence: 99%

“…Finally, with the obtained XLF, we can make predictions on how many sources per redshift bin would be detectable by an MeV experiment with a certain sensitivity. We consider estimated sensitivities of proposed and accepted MeV missions: COSI (point-source sensitivities obtained via private communication; see Tomsick et al 2019); AMEGO-X (Caputo et al 2022); ASTROGAM (point-source sensitivities reported in the mission design proposed for the M7 mission call of ESA; obtained via private communication); and the Lunar Occultation Explorer (LOX; Miller et al 2019). Table 6 reports the predicted sensitivities and number of sources that will be detected by such missions in various redshift bins, and the normalized histogram showing the fraction of sources detected per redshift bin by these missions is shown in the right panel of Figure 15.…”

Section: Prospects For the Mev Rangementioning

confidence: 99%

“…Blazars in general, and MeV blazars in particular, are thought to be possible sources of extragalactic neutrinos (e.g., Murase et al 2014Murase et al , 2016Kadler et al 2016;Aartsen et al 2017;Krauß et al 2018;IceCube Collaboration et al 2018;Buson et al 2022). Taking advantage of the derived best-fit high-energy SED and of the up-to-date XLF, we calculate the number of neutrinos expected to be found in coincidence with MeV blazars detected by a forthcoming MeV mission (de Angelis et al 2018;Tomsick et al 2019;Miller et al 2019;Caputo et al 2022). We follow the methodology described in Krauß et al (2018, and into account physically motivated blazar spectra;…”

Section: Neutrino Predictionsmentioning

confidence: 99%

“…In order to derive blazar contribution to the highenergy cosmic backgrounds, in Section 5 we derive the average BAT-blazar SED from 14 keV to 10 GeV using BAT and LAT data. Knowledge of both the luminosity function and average SED enables us to derive their contribution to the CXB in the hard X-ray regime (14-500 keV; Section 6) as well make predictions for the MeV background (0.5-30 MeV) in light of planned MeV missions like COSI (Tomsick et al 2019) or potentially forthcoming ones like ASTROGAM. Finally, the blazar luminosity function allows us to examine the properties of the parent population of jetted AGNs (Section 7).…”

Section: Introductionmentioning

confidence: 99%

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BASS. XXXIII. Swift-BAT Blazars and Their Jets through Cosmic Time

Marcotulli

Ajello

Urry

et al. 2022

ApJ

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We derive the most up-to-date Swift-Burst Alert Telescope (BAT) blazar luminosity function in the 14–195 keV range, making use of a clean sample of 118 blazars detected in the BAT 105 month survey catalog, with newly obtained redshifts from the BAT Active Galatic Nucleus Spectroscopic Survey. We determine the best-fit X-ray luminosity function for the whole blazar population, as well as for flat-spectrum radio quasars (FSRQs) alone. The main results are: (1) at any redshift, BAT detects the most luminous blazars, above any possible break in their luminosity distribution, which means we cannot differentiate between density and luminosity evolution; (2) the whole blazar population, dominated by FSRQs, evolves positively up to redshift z ∼ 4.3, confirming earlier results and implying lower number densities of blazars at higher redshifts than previously estimated. The contribution of this source class to the cosmic X-ray background at 14–195 keV can range from 5%–18%, while possibly accounting for 100% of the MeV background. We also derived the average 14 keV–10 GeV spectral energy distribution for BAT blazars, which allows us to predict the number counts of sources in the MeV range, as well as the expected number of high-energy (>100 TeV) neutrinos. A mission like COSI will detect 40 MeV blazars, of which two may have coincident neutrino detections. Finally, taking into account beaming selection effects, the distribution and properties of the parent population of these extragalactic jets are derived. We find that the distribution of viewing angles is quite narrow, with most sources aligned within <5° of the line of sight. Moreover, the average Lorentz factor, 〈Γ〉 = 8–12, is lower than previously suggested for these powerful sources.

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Section: Mev Versus Gev Blazarsmentioning

confidence: 99%

Section: Prospects For the Mev Rangementioning

confidence: 99%

Section: Neutrino Predictionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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BASS. XXXIII. Swift-BAT Blazars and Their Jets through Cosmic Time

Marcotulli

Ajello

Urry

et al. 2022

ApJ

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“…Such observations have not been achieved in the two decades since COMPTEL. There are several ongoing or planned projects of the MeV gamma-ray observation, such as COSI-SMEX (Tomsick et al 2019) Lucchetta et al 2022). With these future missions, we need to resolve the individual MeV gamma-ray sources first.…”

Section: Prospects For Future Missionsmentioning

confidence: 99%

MeV Gamma-Ray Source Contribution to the Inner Galactic Diffuse Emission

Tsuji

Inoue

Yoneda

et al. 2023

ApJ

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The origin of the inner Galactic emission, measured by COMPTEL with a flux of ∼10−2 MeV cm−2 s−1 sr−1 in the 1–30 MeV energy range from the inner Galactic region, has remained unsettled since its discovery. In this paper, we elaborate on a model of individual MeV gamma-ray sources unresolved by COMPTEL. This is conducted for sources crossmatched between the Swift-BAT and Fermi-LAT catalogs by interpolating the energy spectra in the hard X-ray and GeV gamma-ray ranges, as well as unmatched sources between the two catalogs. We find that the source contribution to the COMPTEL emission would be at least ∼20%. Combined with the Galactic diffuse emission, which is not well constrained, the COMPTEL emission can be roughly reproduced in some cases.

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