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Publications (10 of 13) Show all publications
Chauvin, M., Florén, H.-G. -., Jackson, M., Kamae, T., Kataoka, J., Kiss, M., . . . Pearce, M. (2019). PoGO + polarimetric constraint on the synchrotron jet emission of Cygnus X-1. Monthly Notices of the Royal Astronomical Society: Letters, 483(1), L138-L143
Open this publication in new window or tab >>PoGO + polarimetric constraint on the synchrotron jet emission of Cygnus X-1
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2019 (English)In: Monthly Notices of the Royal Astronomical Society: Letters, ISSN 1745-3925, Vol. 483, no 1, p. L138-L143Article in journal (Refereed) Published
Abstract [en]

We report a polarimetric constraint on the hard X-ray synchrotron jet emission from the Cygnus X-1 black hole binary system. The observational data were obtained using the PoGO+ hard X-ray polarimeter in 2016 July, when Cygnus X-1 was in the hard state. We have previously reported that emission from an extended corona with a low polarization fraction is dominating, and that the polarization angle is perpendicular to the disc surface. In the soft gamma-ray regime, a highly polarized synchrotron jet is reported with INTEGRAL observations. To constrain the polarization fraction and flux of such a jet component in the hard X-ray regime, we now extend analyses through vector calculations in the Stokes QU plane, where the dominant corona emission and the jet component are considered simultaneously. The presence of another emission component with different polarization angle could partly cancel out the net polarization. The 90 per cent upper limit of the polarization fraction for the additional synchrotron jet component is estimated as <10 per cent, <5 per cent, and <5 per cent for polarization angle perpendicular to the disc surface, parallel to the surface, and aligned with the emission reported by INTEGRAL data, respectively. From the 20-180 keV total flux of 2.6 × 10 -8 erg s -1 cm -2, the upper limit of the polarized flux is estimated as < 3 × 10 -9 erg s -1 cm -2.

Place, publisher, year, edition, pages
Oxford University Press, 2019
Keywords
accretion, accretion discs, techniques: polarimetric, X-rays: binaries, X-rays: individual (Cygnus X-1)
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-248187 (URN)10.1093/mnrasl/sly233 (DOI)000482178200028 ()2-s2.0-85062384117 (Scopus ID)
Note

QC 20190412

Available from: 2019-04-12 Created: 2019-04-12 Last updated: 2019-09-05Bibliographically approved
Chauvin, M., Florén, H.-G., Friis, M., Jackson, M., Kamae, T., Kataoka, J., . . . Pearce, M. (2018). Accretion geometry of the black-hole binary Cygnus X-1 from X-ray polarimetry. Nature Astronomy, 2(8), 652-655
Open this publication in new window or tab >>Accretion geometry of the black-hole binary Cygnus X-1 from X-ray polarimetry
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2018 (English)In: Nature Astronomy, ISSN 2397-3366, Vol. 2, no 8, p. 652-655Article in journal (Refereed) Published
Abstract [en]

Black hole binary (BHB) systems comprise a stellar-mass black hole and a closely orbiting companion star. Matter is transferred from the companion to the black hole, forming an accretion disk, corona and jet structures. The resulting release of gravitational energy leads to the emission of X-rays1. The radiation is affected by special/general relativistic effects, and can serve as a probe for the properties of the black hole and surrounding environment, if the accretion geometry is properly identified. Two competing models describe the disk–corona geometry for the hard spectral state of BHBs, based on spectral and timing measurements2,3. Measuring the polarization of hard X-rays reflected from the disk allows the geometry to be determined. The extent of the corona differs between the two models, affecting the strength of the relativistic effects (such as enhancement of the polarization fraction and rotation of the polarization angle). Here, we report observational results on the linear polarization of hard X-ray emission (19–181 keV) from a BHB, Cygnus X-14, in the hard state. The low polarization fraction, <8.6% (upper limit at a 90% confidence level), and the alignment of the polarization angle with the jet axis show that the dominant emission is not influenced by strong gravity. When considered together with existing spectral and timing data, our result reveals that the accretion corona is either an extended structure, or is located far from the black hole in the hard state of Cygnus X-1.

Place, publisher, year, edition, pages
Nature Publishing Group, 2018
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:kth:diva-228215 (URN)10.1038/s41550-018-0489-x (DOI)000440524400021 ()2-s2.0-85051090128 (Scopus ID)
Note

QC 20180521

Available from: 2018-05-18 Created: 2018-05-18 Last updated: 2019-09-20Bibliographically approved
Chauvin, M., Florén, H.-G. -., Friis, M., Jackson, M., Kamae, T., Kataoka, J., . . . Pearce, M. (2018). Correction: Shedding new light on the crab with polarized X-rays (Scientific Reports DOI: 10.1038/s41598-017-07390-7). Scientific Reports, 8(1), Article ID 7975.
Open this publication in new window or tab >>Correction: Shedding new light on the crab with polarized X-rays (Scientific Reports DOI: 10.1038/s41598-017-07390-7)
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2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, no 1, article id 7975Article in journal (Refereed) Published
Abstract [en]

This Article contains a typographical error in the legend of Figure 2. "Gaussian 1, 2 and 3& #x1D70E;" should read: "Gaussian 1, 2 and 3σ". 

Place, publisher, year, edition, pages
Nature Publishing Group, 2018
Keywords
erratum
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-236576 (URN)10.1038/s41598-018-24853-7 (DOI)000432341000001 ()2-s2.0-85047251454 (Scopus ID)
Note

Export Date: 22 October 2018; Erratum; Correspondence Address: Pearce, M.; KTH Royal Institute of Technology, Department of PhysicsSweden; email: pearce@kth.se. QC 20181126

Available from: 2018-11-26 Created: 2018-11-26 Last updated: 2018-11-26Bibliographically approved
Chauvin, M., Floren, H.-G. -., Friis, M., Jackson, M., Kamae, T., Kataoka, J., . . . Pearce, M. (2018). The PoGO plus view on Crab off-pulse hard X-ray polarization. Monthly notices of the Royal Astronomical Society, 477(1), L45-L49
Open this publication in new window or tab >>The PoGO plus view on Crab off-pulse hard X-ray polarization
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2018 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 477, no 1, p. L45-L49Article in journal (Refereed) Published
Abstract [en]

The linear polarization fraction (PF) and angle of the hard X-ray emission from the Crab provide unique insight into high-energy radiation mechanisms, complementing the usual imaging, timing, and spectroscopic approaches. Results have recently been presented by two missions operating in partially overlapping energy bands, PoGO+ (18-160 keV) and AstroSat CZTI (100-380 keV). We previously reported PoGO+ results on the polarization parameters integrated across the light curve and for the entire nebula-dominated off-pulse region. We now introduce finer phase binning, in light of the AstroSat CZTI claim that the PF varies across the off-pulse region. Since both missions are operating in a regime where errors on the reconstructed polarization parameters are non-Gaussian, we adopt a Bayesian approach to compare results from each mission. We find no statistically significant variation in off-pulse polarization parameters, neither when considering the mission data separately nor when they are combined. This supports expectations from standard high-energy emission models.

Place, publisher, year, edition, pages
Oxford University Press, 2018
Keywords
instrumentation: polarimeters, methods: statistical
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:kth:diva-241233 (URN)10.1093/mnrasl/sly027 (DOI)000454420400010 ()
Note

QC 20190117

Available from: 2019-01-17 Created: 2019-01-17 Last updated: 2019-01-18Bibliographically approved
Chauvin, M., Friis, M., Jackson, M., Kawano, T., Kiss, M., Mikhalev, V., . . . Pearce, M. (2017). Calibration and performance studies of the balloon-borne hard X-ray polarimeter PoGO. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 859, 125-133
Open this publication in new window or tab >>Calibration and performance studies of the balloon-borne hard X-ray polarimeter PoGO
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2017 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 859, p. 125-133Article in journal (Refereed) Published
Abstract [en]

Polarimetric observations of celestial sources in the hard X-ray band stand to provide new information on emission mechanisms and source geometries. PoGO+ is a Compton scattering polarimeter (20-150 keV) optimised for the observation of the Crab (pulsar and wind nebula) and Cygnus X-1 (black hole binary), from a stratospheric balloon-borne platform launched from the Esrange Space Centre in summer 2016. Prior to flight, the response of the polarimeter has been studied with polarised and unpolarised X-rays allowing a Geant4-based simulation model to be validated. The expected modulation factor for Crab observations is found to be M-Crab = (41.75 +/- 0.85)%, resulting in an expected Minimum Detectable Polarisation (MDP) of 7.3% for a 7 day flight. This will allow a measurement of the Crab polarisation parameters with at least 5 sigma statistical significance assuming a polarisation fraction similar to 20% - a significant improvement over the PoGOLite Pathfinder mission which flew in 2013 and from which the PoGO+ design is developed.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2017
Keywords
X-ray, Polarisation, Compton scattering, Scientific ballooning, Crab, Cygnus X-1, Monte Carlo simulations
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-219572 (URN)10.1016/j.nima.2017.03.027 (DOI)000402464700018 ()2-s2.0-85018696451 (Scopus ID)
Note

QC 20171207

Available from: 2017-12-07 Created: 2017-12-07 Last updated: 2018-05-21Bibliographically approved
Chauvin, M., Floren, H.-G. -., Jackson, M., Kamae, T., Kawano, T., Kiss, M., . . . Pearce, M. (2016). Observation of polarized hard X-ray emission from the Crab by the PoGOLite Pathfinder. Monthly notices of the Royal Astronomical Society, 456(1), L84-L88
Open this publication in new window or tab >>Observation of polarized hard X-ray emission from the Crab by the PoGOLite Pathfinder
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2016 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 456, no 1, p. L84-L88Article in journal (Refereed) Published
Abstract [en]

We have measured the linear polarization of hard X-ray emission from the Crab in a previously unexplored energy interval, 20-120 keV. The introduction of two new observational parameters, the polarization fraction and angle stands to disentangle geometrical and physical effects, thereby providing information on the pulsar wind geometry and magnetic field environment. Measurements are conducted using the PoGOLite Pathfinder - a balloon-borne polarimeter. Polarization is determined by measuring the azimuthal Compton scattering angle of incident X-rays in an array of plastic scintillators housed in an anticoincidence well. The polarimetric response has been characterized prior to flight using both polarized and unpolarized calibration sources. We address possible systematic effects through observations of a background field. The measured polarization fraction for the integrated Crab light curve is 18.4(-10.6)(+9.8) per cent, corresponding to an upper limit (99 per cent credibility) of 42.4 per cent, for a polarization angle of (149.2 +/- 16.0)degrees.

Place, publisher, year, edition, pages
Oxford University Press, 2016
Keywords
instrumentation: polarimeters, techniques: polarimetric, stars: neutron, pulsars: individual: the Crab pulsar
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:kth:diva-182840 (URN)10.1093/mnrasl/slv177 (DOI)000368010000018 ()2-s2.0-84959175886 (Scopus ID)
Note

QC 20160224

Available from: 2016-02-24 Created: 2016-02-23 Last updated: 2018-05-21Bibliographically approved
Chauvin, M., Jackson, M., Kawano, T., Kiss, M., Kole, M., Mikhalev, V., . . . Pearce, M. (2016). Preflight performance studies of the PoGOLite hard X-ray polarimeter. Astroparticle physics, 72, 1-10
Open this publication in new window or tab >>Preflight performance studies of the PoGOLite hard X-ray polarimeter
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2016 (English)In: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 72, p. 1-10Article in journal (Refereed) Published
Abstract [en]

Polarimetric studies of astrophysical sources can make important contributions to resolve the geometry of the emitting region and determine the photon emission mechanism. PoGOLite is a balloon-borne polarimeter operating in the hard X-ray band (25-240 key), with a Pathfinder mission focussing on Crab observations. Within the polarimeter, the distribution of Compton scattering angles is used to determine the polarisation fraction and angle of incident photons. To assure an unbiased measurement of the polarisation during a balloon flight it is crucial to characterise the performance of the instrument before the launch. This paper presents the results of the PoGOLite calibration tests and simulations performed before the 2013 balloon flight. The tests performed confirm that the polarimeter does not have any intrinsic asymmetries and therefore does not induce bias into the measurements. Generally, good agreement is found between results from test data and simulations which allows the polarimeter performance to be estimated for Crab observations.

Keywords
Polarimeter, X-ray, Crab, Balloon
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-175895 (URN)10.1016/j.astropartphys.2015.05.003 (DOI)000362143000001 ()2-s2.0-84933575687 (Scopus ID)
Funder
Swedish National Space BoardSwedish Research CouncilKnut and Alice Wallenberg Foundation
Note

QC 20151113

Available from: 2015-11-13 Created: 2015-10-26 Last updated: 2017-12-01Bibliographically approved
Chauvin, M., Florén, H.-G. -., Jackson, M., Kamae, T., Kawano, T., Kiss, M., . . . Pearce, M. (2016). The design and flight performance of the PoGOLite Pathfinder balloon-borne hard X-ray polarimeter. Experimental astronomy (Print), 41(1), 17-41
Open this publication in new window or tab >>The design and flight performance of the PoGOLite Pathfinder balloon-borne hard X-ray polarimeter
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2016 (English)In: Experimental astronomy (Print), ISSN 0922-6435, E-ISSN 1572-9508, Vol. 41, no 1, p. 17-41Article in journal (Refereed) Published
Abstract [en]

In the 50 years since the advent of X-ray astronomy there have been many scientific advances due to the development of new experimental techniques for detecting and characterising X-rays. Observations of X-ray polarisation have, however, not undergone a similar development. This is a shortcoming since a plethora of open questions related to the nature of X-ray sources could be resolved through measurements of the linear polarisation of emitted X-rays. The PoGOLite Pathfinder is a balloon-borne hard X-ray polarimeter operating in the 25-240 keV energy band from a stabilised observation platform. Polarisation is determined using coincident energy deposits in a segmented array of plastic scintillators surrounded by a BGO anticoincidence system and a polyethylene neutron shield. The PoGOLite Pathfinder was launched from the SSC Esrange Space Centre in July 2013. A near-circumpolar flight was achieved with a duration of approximately two weeks. The flight performance of the Pathfinder design is discussed for the three Crab observations conducted. The signal-to-background ratio for the observations is shown to be 0.25 ±0.03 and the Minimum Detectable Polarisation (99 % C.L.) is (28.4 ±2.2) %. A strategy for the continuation of the PoGOLite programme is outlined based on experience gained during the 2013 maiden flight.

Keywords
Crab, Scientific ballooning, X-ray polarimetry
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-175006 (URN)10.1007/s10686-015-9474-x (DOI)000369518700002 ()2-s2.0-84957436141 (Scopus ID)
Funder
Swedish National Space BoardKnut and Alice Wallenberg FoundationSwedish Research CouncilGöran Gustafsson Foundation for promotion of scientific research at Uppala University and Royal Institute of Technology
Note

QC 20160304

Available from: 2015-12-01 Created: 2015-10-09 Last updated: 2017-12-01Bibliographically approved
Sofitta, P., Pearce, M., Axelsson, M., Chauvin, M., Burgess, M., Kiss, M., . . . et al., . (2016). XIPE the X-ray Imaging Polarimetry Explorer. In: Proceedings of SPIE: . Paper presented at Conference on Space Telescopes and Instrumentation - Ultraviolet to Gamma Ray, Edinburgh, SCOTLAND, JUN 26-JUL 01, 2016. SPIE - International Society for Optical Engineering, 9905, Article ID UNSP 990515.
Open this publication in new window or tab >>XIPE the X-ray Imaging Polarimetry Explorer
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2016 (English)In: Proceedings of SPIE, SPIE - International Society for Optical Engineering, 2016, Vol. 9905, article id UNSP 990515Conference paper, Published paper (Refereed)
Abstract [en]

XIPE, the X-ray Imaging Polarimetry Explorer, is a mission dedicated to X-ray Astronomy. At the time of writing XIPE is in a competitive phase A as fourth medium size mission of ESA (M4). It promises to reopen the polarimetry window in high energy Astrophysics after more than 4 decades thanks to a detector that efficiently exploits the photoelectric effect and to X-ray optics with large effective area. XIPE uniqueness is time-spectrally-spatially- resolved X-ray polarimetry as a breakthrough in high energy astrophysics and fundamental physics. Indeed the payload consists of three Gas Pixel Detectors at the focus of three X-ray optics with a total effective area larger than one XMM mirror but with a low weight. The payload is compatible with the fairing of the Vega launcher. XIPE is designed as an observatory for X- ray astronomers with 75% of the time dedicated to a Guest Observer competitive program and it is organized as a consortium across Europe with main contributions from Italy, Germany, Spain, United Kingdom, Poland, Sweden.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2016
Keywords
Gas Pixel Detector, Polarimetry, X-ray Astronomy, X-ray optics
National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:kth:diva-202016 (URN)10.1117/12.2233046 (DOI)000387731500030 ()2-s2.0-85003741930 (Scopus ID)978-1-5106-0189-5 (ISBN)978-1-5106-0190-1 (ISBN)
Conference
Conference on Space Telescopes and Instrumentation - Ultraviolet to Gamma Ray, Edinburgh, SCOTLAND, JUN 26-JUL 01, 2016
Note

QC 20170216

Available from: 2017-02-16 Created: 2017-02-16 Last updated: 2017-02-16Bibliographically approved
Kole, M., Chauvin, M., Fukazawa, Y., Fukuda, K., Ishizu, S., Jackson, M., . . . Yanagida, T. (2015). PoGOLino: A scintillator-based balloon-borne neutron detector. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 770, 68-75
Open this publication in new window or tab >>PoGOLino: A scintillator-based balloon-borne neutron detector
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2015 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 770, p. 68-75Article in journal (Refereed) Published
Abstract [en]

PoGOLino is a balloon borne scintillator-based experiment developed to study the largely unexplored high altitude neutron environment at high geomagnetic latitudes. The instrument comprises two detectors LhaL make use of LiCAF, a novel neutron sensitive scintillator, sandwiched by [GO crystals for background reduction. The experiment was launched on March 20th 2013 from the [orange Space Centre, Northern Sweden (geomagnetic latitude of 65 degrees), for a three hour flight during which the instrument Look data up loan altitude of 30.9 km. The detector design and ground calibration results are presented together with the measurement results from the balloon flight.

Keywords
Neutron detection, Balloon-borne, Astroparticle physics, Phoswich scintillator, LiCAF
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-158258 (URN)000345855200012 ()2-s2.0-84908439343 (Scopus ID)
Funder
Swedish National Space Board
Note

QC 20150107

Available from: 2015-01-07 Created: 2015-01-07 Last updated: 2017-05-19Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-1999-2161

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