Article
Astronomy & Astrophysics
Yuto Mochizuki, Misaki Mizumoto, Ken Ebisawa
Summary: This study re-analyzed the X-ray data of Mrk 766 and identified complex Fe-K line features and X-ray spectral variations, including blue-shifted Fe-K absorption lines caused by ultrafast outflows, narrow emission lines from distant material, broad emission lines from inner-disc reflections, and weak emission lines possibly due to resonance scattering in the outflows.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Margaret Z. Buhariwalla, Luigi C. Gallo, J. Mao, S. Komossa, J. Jiang, A. Gonzalez, D. Grupe
Summary: Mrk 1239 is a highly polarized NLS1, and its 0.3-3 keV spectrum has remained consistent over more than two decades. Previous analysis suggested that the soft X-ray band was mainly dominated by emission lines from the distant host galaxy. New XMM-Newton data of Mrk 1239 reveal ionized emission lines from two distinct plasmas, one collisionally ionized and the other photoionized. The results improve significantly when allowing the outflow of photoionized material at a velocity matching the forbidden O VII emission line.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
F. M. Vincentelli, I McHardy, E. M. Cackett, A. J. Barth, K. Horne, M. Goad, K. Korista, J. Gelbord, W. Brandt, R. Edelson, J. A. Miller, M. Pahari, B. M. Peterson, T. Schmidt, R. D. Baldi, E. Breedt, J. V. Hernandez Santisteban, E. Romero-Colmenero, M. Ward, D. R. A. Williams
Summary: The intensive continuum reverberation mapping study of Mrk 110, a high accretion-rate Seyfert galaxy, showed significant variability at all wavebands. Analysis of intraband lags revealed different behaviors on different time-scales, indicating an interplay between emission from the accretion disc and diffuse continuum radiation from the broad-line region.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Francesca Panessa, Miguel Perez-Torres, Lorena Hernandez-Garcia, Piergiorgio Casella, Marcello Giroletti, Monica Orienti, Ranieri D. Baldi, Loredana Bassani, Maria Teresa Fiocchi, Fabio La Franca, Angela Malizia, Ian McHardy, Fabrizio Nicastro, Luigi Piro, Federico Vincentelli, David R. A. Williams, Pietro Ubertini
Summary: This study presents evidence for significant radio variability in high accreting and radio-quiet Narrow Line Seyfert 1 (NLSy1) type Mrk 110, suggesting a small emitting region and a possible origin from a low-power jet or an outflowing corona.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Bing Lyu, Zhen Yan, Wenfei Yu, Qingwen Wu
Summary: The physical mechanism behind the changing-look phenomenon in active galactic nuclei (AGNs) is still unclear, but observations based on multiwavelength spectral and flux variations have revealed some interesting phenomena. For example, there is a time lag of approximately 20 days between optical/UV and X-ray emissions, and a 20% decrease in 5 GHz radio flux during a specific phase. Anticorrelations were found between X-ray photon index (Gamma) and optical-to-X-ray spectral index (alpha(ox)) with the Eddington scaled 2-10 keV X-ray luminosity (L-X/L-Edd) in one phase, suggesting a regulation by the evolution of the accretion disc.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Samuzal Barua, V Jithesh, Ranjeev Misra, Biman J. Medhi, Oluwashina Adegoke
Summary: This study uses X-ray observations to reveal the variability characteristics and physical mechanism of the X-ray spectrum of Mrk 478.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Arghajit Jana, Neeraj Kumari, Prantik Nandi, Sachindra Naik, Arka Chatterjee, Gaurava K. Jaisawal, Kimitake Hayasaki, Claudio Ricci
Summary: The study on the changing-look active galactic nucleus NGC 1566 during its outburst in June 2018 revealed a significant increase in X-ray intensity. Analysis of the X-ray data and modeling showed a strong soft X-ray excess during the outburst, potentially originating from the warm Comptonizing region in the inner accretion disc. The sudden rise in luminosity observed is likely caused by an increase in the accretion rate.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Prantik Nandi, Arka Chatterjee, Sandip K. Chakrabarti, Broja G. Dutta
Summary: The study analyzed the long-term X-ray spectral and temporal properties of a bare-type AGN, revealing that spectral variations can be explained by changes in accretion dynamics. The correlation between X-ray time delays and soft-excess suggests a common physical process.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Yerong Xu, Ciro Pinto, Daniele Rogantini, Stefano Bianchi, Matteo Guainazzi, Erin Kara, Chichuan Jin, Giancarlo Cusumano
Summary: We studied the ultrafast outflow (UFO) in a highly accreting narrow-line Seyfert 1 (NLS1) galaxy, Mrk 1044, and found that it responds quickly to source variability and its velocity increases with X-ray flux. We conservatively estimated the kinetic energy of the UFO to be 4.4% of the Eddington limit, reaching the theoretical criterion to affect the host galaxy evolution. We also observed a rare blueshift of emission lines in Mrk 1044, suggesting a correlation between the blueshift and the source accretion rate that can be further investigated in future studies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
R. Brogan, M. Krumpe, D. Homan, T. Urrutia, T. Granzer, B. Husemann, J. Neumann, M. Gaspari, S. P. Vaughan, S. M. Croom, F. Combes, M. Perez Torres, A. Coil, R. McElroy, N. Winkel, M. Singha
Summary: We study a major outburst in the Mrk 1018 Seyfert galaxy, using optical and other wavelength data to investigate the response of the AGN structure. Our results show that while some parameters have changed, the shape of the H/3 and Ha lines remains unchanged, the primary X-ray spectral components are unaffected, and there is a rapid and extended enhancement in the infrared emission.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
P. Lira, M. Kishimoto, R. W. Goosmann, R. Campos, D. Axon, M. Elvis, A. Lawrence, B. M. Peterson, A. Robinson
Summary: This study presents high signal-to-noise optical spectropolarimetric observations of Seyfert 1 galaxies NGC3783 and Mrk 509, revealing complex structures and 'M'-shaped profiles in polarized emissions across Balmer lines. The results suggest this could be a common trait in Seyfert 1 galaxies. Modelled using the STOKES radiative transfer code, the study provides compelling new evidence for the presence of nuclear winds in these galaxies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Jun Yang, Ilse van Bemmel, Zsolt Paragi, S. Komossa, Feng Yuan, Xiaolong Yang, Tao An, J. Y. Koay, C. Reynolds, J. B. R. Oonk, Xiang Liu, Qingwen Wu
Summary: The nearby galaxy Mrk 590 experienced dramatic Seyfert type changes and continuum outbursts in the past, with a faint radio jet possibly resulting from intense activity in the AGN. The finding of the faint jet supports the variable accretion as the origin of type changes in Mrk 590.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
D. Tagliacozzo, A. Marinucci, F. Ursini, G. Matt, S. Bianchi, L. Baldini, T. Barnouin, N. Cavero Rodriguez, A. De Rosa, L. Di Gesu, M. Dovciak, D. Harper, A. Ingram, V Karas, D. E. Kim, H. Krawczynski, G. Madejski, F. Marin, R. Middei, H. L. Marshall, F. Muleri, C. Panagiotou, P. -O Petrucci, J. Podgorny, J. Poutanen, S. Puccetti, P. Soffitta, F. Tombesi, A. Veledina, W. Zhang, I Agudo, L. A. Antonelli, M. Bachetti, W. H. Baumgartner, R. Bellazzini, S. D. Bongiorno, R. Bonino, A. Brez, N. Bucciantini, F. Capitanio, S. Castellano, E. Cavazzuti, C. -T Chen, S. Ciprini, E. Costa, E. Del Monte, N. Di Lalla, A. Di Marco, I Donnarumma, V Doroshenko, S. R. Ehlert, T. Enoto, Y. Evangelista, S. Fabiani, R. Ferrazzoli, J. A. Garcia, S. Gunji, J. Heyl, W. Iwakiri, S. G. Jorstad, P. Kaaret, F. Kislat, T. Kitaguchi, J. J. Kolodziejczak, F. La Monaca, L. Latronico, I Liodakis, S. Maldera, A. Manfreda, A. P. Marscher, F. Massaro, I Mitsuishi, T. Mizuno, M. Negro, C-Y Ng, S. L. O'Dell, N. Omodei, C. Oppedisano, A. Papitto, G. G. Pavlov, A. L. Peirson, M. Perri, M. Pesce-Rollins, M. Pilia, A. Possenti, B. D. Ramsey, J. Rankin, A. Ratheesh, O. J. Roberts, R. W. Romani, C. Sgro, P. Slane, G. Spandre, D. A. Swartz, T. Tamagawa, F. Tavecchio, R. Taverna, Y. Tawara, A. F. Tennant, N. E. Thomas, A. Trois, S. S. Tsygankov, R. Turolla, J. Vink, M. C. Weisskopf, K. Wu, F. Xie, S. Zane
Summary: We report the second observation of the radio-quiet active galactic nucleus MCG-05-23-16 using the Imaging X-ray Polarimetry Explorer. The observation results show a polarization degree of 1.6 +/- 0.7 in the 2-8 keV range, with an upper limit of 3.2%, and are compared with Monte Carlo simulations using the MONK code.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
D. Costanzo, M. Dadina, C. Vignali, B. De Marco, M. Cappi, P. O. Petrucci, S. Bianchi, G. A. Kriss, J. S. Kaastra, M. Mehdipour, E. Behar, G. A. Matzeu
Summary: The X-ray time-resolved spectral analysis of NGC 3783 aimed to detect transient features in the Fe K line complex to study the dynamics of the innermost accretion flow. The study found discrete features in emission and absorption at different times, with higher significance in the obscured dataset, indicating a change in energy distribution and clustering of features at different energies. Residual maps suggest a possible modulation of the Fe K alpha line intensity related to the clumpiness of the absorbing medium.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
S. Chalise, A. M. Lohfink, J. Chauhan, T. D. Russell, D. J. K. Buisson, L. Mallick
Summary: The X-ray spectra of some active galactic nuclei (AGNs) show a soft X-ray excess, which can be attributed to relativistic ionized reflection, extreme blurring of reprocessed emission from the innermost region of the accretion disc, or Comptonization from a warm corona. In the case of Mrk 926, it is difficult to determine the exact cause of the observed soft excess, although a warm coronal-like component is slightly favored by the data. The study also detects an optically thin radio component in Mrk 926, which requires further multiwavelength observations to investigate its origin.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Instruments & Instrumentation
A. L. Peirson, R. W. Romani, H. L. Marshall, J. F. Steiner, L. Baldini
Summary: This study introduces a method to enhance the sensitivity of X-ray telescopic observations using deep convolutional neural networks for more accurate processing of X-ray data. The improved model analysis has been validated in experiments and achieved significant results.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
(2021)
Article
Astronomy & Astrophysics
Houdun Zeng, Yuliang Xin, Shuinai Zhang, Siming Liu
Summary: Recent multiwavelength observations show that HESS J1912+101 may represent a peculiar stage of SNR evolution dominating the acceleration of TeV cosmic rays. Analysis of multiple SNRs suggests that gamma-ray emission mainly originates from SNRs with hard gamma-ray spectra.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Paolo Soffitta, Niccolo' Bucciantini, Eugene Churazov, Enrico Costa, Michal Dovciak, Hua Feng, Jeremy Heyl, Adam Ingram, Keith Jahoda, Philip Kaaret, Timothy Kallman, Vladimir Karas, Ildar Khabibullin, Henric Krawczynski, Julien Malzac, Frederic Marin, Herman Marshall, Giorgio Matt, Fabio Muleri, Carole Mundell, Mark Pearce, Pierre-Olivier Petrucci, Juri Poutanen, Roger Romani, Andrea Santangelo, Gianpiero Tagliaferri, Roberto Taverna, Roberto Turolla, Jacco Vink, Silvia Zane
Summary: X-ray polarimetry has been considered a 'holy grail' in X-ray astronomy, and after more than 40 years, the field is now experiencing a resurgence. Recent successful operation of an X-ray polarimeter on a Cube-sat nano-satellite has paved the way for future missions such as IXPE and eXTP, which are expected to be launched in 2021 and 2027 respectively. Although the specific discoveries of these missions are hard to predict due to their exploratory nature, plans for follow-up missions are already being formulated.
EXPERIMENTAL ASTRONOMY
(2021)
Article
Astronomy & Astrophysics
M. J. Middleton, D. J. Walton, W. Alston, T. Dauser, S. Eikenberry, Y-F Jiang, A. C. Fabian, F. Fuerst, M. Brightman, H. Marshall, M. Parker, C. Pinto, F. A. Harrison, M. Bachetti, D. Altamirano, A. J. Bird, G. Perez, J. Miller-Jones, P. Charles, S. Boggs, F. Christensen, W. Craig, K. Forster, B. Grefenstette, C. Hailey, K. Madsen, D. Stern, W. Zhang
Summary: SS433 is the only known Galactic binary system that persistently accretes at highly super-critical rates. Observations with NuSTAR in the hard X-ray band across multiple phases revealed intriguing findings about the system's inner regions. The discovery of a narrow, approximately 100 second lag provides insight into atomic processes in outflowing material, potentially allowing for the mapping of a super-critical outflow for the first time.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Herman L. Marshall
Summary: This study utilizes the maximum likelihood method to estimate the minimum detectable polarization, taking into account uncertainties in event track position angles. By deriving a simple relationship between track angle uncertainties and the energy-dependent modulation function, the process is made more straightforward.
ASTRONOMICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Bradford Snios, Daniel A. Schwartz, Aneta Siemiginowska, Malgosia Sobolewska, Mark Birkinshaw, C. C. Cheung, Doug B. Gobeille, Herman L. Marshall, Giulia Migliori, John F. C. Wardle, Diana M. Worrall
Summary: Chandra X-ray observations of 14 radio-loud quasars at redshifts 3 < z < 4 show detected X-ray features, measured fluxes, and compared spectral properties with optical and radio emission, indicating an independent X-ray emission mechanism with redshift.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Yuhan Yao, S. R. Kulkarni, K. C. Gendreau, Gaurava K. Jaisawal, Teruaki Enoto, Brian W. Grefenstette, Herman L. Marshall, Javier A. Garcia, R. M. Ludlam, Sean N. Pike, Mason Ng, Liang Zhang, Diego Altamirano, Amruta Jaodand, S. Bradley Cenko, Ronald A. Remillard, James F. Steiner, Hitoshi Negoro, Murray Brightman, Amy Lien, Michael T. Wolff, Paul S. Ray, Koji Mukai, Zorawar Wadiasingh, Zaven Arzoumanian, Nobuyki Kawai, Tatehiro Mihara, Tod E. Strohmayer
Summary: AT2019wey is classified as a Galactic low-mass X-ray binary with a black hole or neutron star accretor. It stayed in the low/hard state from December 2019 to August 2020, then transitioned to the hard-intermediate state. During the first six months, it had a flux of around 1 mCrab with a power-law X-ray spectrum. From June to August 2020, the brightness increased to around 20 mCrab.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Paul B. Hemphill, Norbert S. Schulz, Herman L. Marshall, Deepto Chakrabarty
Summary: This study presents an analysis of the ultracompact X-ray binary 4U 1626-67 using Chandra/LETGS observations, focusing on properties like donor star characteristics, plasma parameters, and elemental abundance ratios. The findings reveal constraints on system inclination, inner disk radius, donor mass, neon abundance, iron abundance, and magnesium abundance in the system, offering valuable insights into the structure and composition of the source.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Missagh Mehdipour, Gerard A. Kriss, Yair Krongold, Anna Lia Longinotti, Elisa Costantini, Anjali Gupta, Smita Mathur, Fabrizio Nicastro, Francesca Panessa, Debopam Som
Summary: This study reports the discovery of a UV absorption counterpart of a low-ionization X-ray ultrafast outflow (UFO) in a narrow-line Seyfert 1 galaxy. The UV signature is observed in the far-UV spectrum taken with the COS on the HST. The high-resolution UV spectroscopy and photoionization modeling reveal the presence of multiple ionization and velocity components of the UFOs in the galaxy.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Jia Sun, Robert A. Gutermuth, Hongchi Wang, Shuinai Zhang, Min Long
Summary: Young stellar clusters are likely to inherit the hierarchical spatial distribution from their natal molecular cloud. Through the study of young stellar objects in the W40-Serpens South region, it is found that their distribution exhibits hierarchical properties and is closely related to fractal dimensions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Jia Sun, Robert A. Gutermuth, Hongchi Wang, Miaomiao Zhang, Shuinai Zhang, Yuehui Ma, Xinyu Du, Min Long
Summary: This study compiles a catalog of YSOs in the W40-Serpens South region based on near-infrared observations. The YSOs are classified and found to be well correlated with the filamentary structures of molecular clouds. The distribution of YSOs in this star-forming region appears to be a mixture of both primordial and somewhat evolved YSOs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Anna Lia Longinotti, Q. Salome, C. Feruglio, Y. Krongold, S. Garcia-Burillo, M. Giroletti, F. Panessa, C. Stanghellini, O. Vega, V. M. Patino-alvarez, V Chavushyan, M. Elias-Chavez, A. Robleto-Orus
Summary: This paper reports on NOEMA observations to constrain the spatial scale of the molecular outflow in the Narrow Line Seyfert 1 Galaxy IRAS17020 + 4544. The high-velocity gas in the outflow is not coincident with the rotation pattern of the CO gas in the host galaxy disc. The estimated mass outflow rate shows that this powerful galaxy-scale outflow is consistent with energy conservation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Proceedings Paper
Astronomy & Astrophysics
Paolo Soffitta, Primo Attina, Luca Baldini, Mattia Barbanera, Wayne H. Baumgartner, Ronaldo Bellazzini, Jeff Bladt, Stephen D. Bongiorno, Alessandro Brez, Simone Castellano, Rita Carpentiero, Marco Castronuovo, Luca Cavalli, Elisabetta Cavazzuti, Fabio D'Amico, Saverio Citraro, Enrico Costa, William D. Deininger, ELisa D'Alba, Ettore Del Monte, Kutis L. Diets, Niccolo Di Lalla, Alessandro Di Marco, Guseppe Di Persio, Immacolata Donnarumma, Sergio Fabiani, Riccardo Ferrazzoli, Larry Guy, Michael Head, William Kalinowski, Jeffery Kolodziejczak, Luca Latronico, Carlo Lefevre, Paolo Lorenzi, Leonardo Lucchesi, Simone Maldera, Alberto Manfreda, Elio Mangraviti, Herman L. Marshall, James Masciarelli, Giorgio Matt, Massimo Minuti, Rondal Mize, Fabio Muleri, Hikmat Nasimi, Barbara Negri, Alessio Nuti, Stephen L. O'Dell, Leonardo Orsini, Darren Osborne, Maura Pilia, Matteo Perri, Melissa Pesce-Rollins, Colin Peterson, Michele Pinchera, Simonetta Puccetti, Brian Ramsey, Ajay Ratheesh, Roger W. Romani, Paolo Sarra, Francesco Santoli, Andrea Sciortino, Christopher Schroeder, Carmelo Sgro, Gloria Spandre, Allyn F. Tennant, Antonino Tobia, Nicholas E. Thomas, Alessio Trois, Marco Vimercati, Jeffrey Wedmnore, Martin C. Weisskopf, Fei Xie, Francesco Zanetti, Cheryl Alexander, D. Zachery Allen, Fabrizio Amici, L. Angelo Antonelli, Spencer Antoniak, Matteo Bachetti, Randy M. Baggett, Raffaella Bonino, Fabio Borotto, Shawn Breeding, Daniele Brienza, H. Kyle Bygott, Claudia Cardelli, Marco Ceccanti, Mauro Centrone, David Dolan, Yuri Evangelista, Kevin Ferrant, MacKenzie Ferrie, Joseph Footdale, Brent Forsyth, Michele Foster, Benjamin Garelick, Eli Gurnee, Grant Hibbard, Sandra R. Johnson, Sandra Johnson, Erik Kelly, Kiranmayee Kilaru, Fabio La Monaca, Shelley Le Roy, Pasqualino Loffredo, Tyler Maddox, Guido Magazzu, Marco Marengo, Alessandra Marrocchesi, Francesco Massaro, Jeffrey McCracken, Michael McEachen, Paolo Mereu, Scott Mitchell, Ikuyuki Mitsuishi, James (Tony) Moore, Alfredo Morbidini, Federico Mosti, Michela Nigro, Chiara Oppedisano, Richard Pacheco, Alessandro Paggi, Steven D. Pavelitz, Cristina Pentz, Raffaele Piazzolla, Brad Porter, Alessandro Profeti, Jaganathan Ranganathan, John Rankin, Noah Root, Alda Rubini, Stephanie Ruswick, Javier Sanchez, Emanuele Scalise, Sara Schindhelm, Tim Seek, Chet O. Speegle, Toru Tamagawa, Marcello Tardiola, Amy L. Walden, Bruce Weddendorf, David Welch
Summary: IXPE will add linear polarization to the usual features of X-ray astronomy missions, expanding the available information and providing meaningful observations. Thanks to its imaging capabilities and sensitivity, it will produce polarization maps of X-ray-bright extended sources and phase-resolved polarimetry of bright pulsating X-ray sources.
SPACE TELESCOPES AND INSTRUMENTATION 2020: ULTRAVIOLET TO GAMMA RAY
(2021)
Proceedings Paper
Astronomy & Astrophysics
Herman L. Marshall, Sarah N. T. Heine, Alan Garner, Eric M. Gullikson, H. Moritz Gunther, Christopher Leitz, Rebecca Masterson, Eric D. Miller, William Zhang, Rozenn Boissay-Malaquin, Ilaria Caiazzo, Deepto Chakrabarty, Rosemary Davidson, Luigi C. Gallo, Ralf K. Heilmann, Jeremy Heyl, Erin Kara, Alan Marscher, Norbert S. Schulz
Summary: The text describes a new implementation of a broad-band soft X-ray polarimeter, PiSoX, designed for NASA's Astrophysics Pioneers program. The system is optimized for polarimetry and can achieve high polarization modulation factors. It uses lightweight Si mirrors and efficient, blazed gratings to disperse the spectrum and determine source polarization parameters through satellite rotation.
SPACE TELESCOPES AND INSTRUMENTATION 2020: ULTRAVIOLET TO GAMMA RAY
(2021)
Article
Astronomy & Astrophysics
Herman L. Marshall
Summary: This study derives an optimal estimate for Stokes parameters in X-ray astronomy, particularly for sources with instruments that have modulation factors varying significantly with energy and weak or mildly polarized signals. Optimal estimators are provided for both binned and unbinned data, showing significant improvement in polarization measurement by broadening the band of analysis or improving the modulation factor, with potential additional enhancement through methods like using neural networks. The level of improvement achieved depends on the spectral shape and instrument response functions.
ASTROPHYSICAL JOURNAL
(2021)