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Observations of 4U 1626–67 with the Imaging X-Ray Polarimetry Explorer

Marshall, Herman L. and Ng, Mason and Rogantini, Daniele and Heyl, Jeremy and Tsygankov, Sergey S. and Poutanen, Juri and Costa, Enrico and Zane, Silvia and Malacaria, Christian and Agudo, Iván and Antonelli, Lucio A. and Bachetti, Matteo and Baldini, Luca and Baumgartner, Wayne H. and Bellazzini, Ronaldo and Bianchi, Stefano and Bongiorno, Stephen D. and Bonino, Raffaella and Brez, Alessandro and Bucciantini, Niccolò and Capitanio, Fiamma and Castellano, Simone and Cavazzuti, Elisabetta and Ciprini, Stefano and De Rosa, Alessandra and Monte, Ettore Del and Gesu, Laura Di and Lalla, Niccolò Di and Marco, Alessandro Di and Donnarumma, Immacolata and Doroshenko, Victor and Dovčiak, Michal and Ehlert, Steven R. and Enoto, Teruaki and Evangelista, Yuri and Fabiani, Sergio and Ferrazzoli, Riccardo and García, Javier A. and Gunji, Shuichi and Hayashida, Kiyoshi and Iwakiri, Wataru and Jorstad, Svetlana G. and Karas, Vladimir and Kitaguchi, Takao and Kolodziejczak, Jeffery J. and Krawczynski, Henric and La Monaca, Fabio and Latronico, Luca and Liodakis, Ioannis and Maldera, Simone and Manfreda, Alberto and Marin, Frédéric and Marinucci, Andrea and Marscher, Alan P. and Matt, Giorgio and Mitsuishi, Ikuyuki and Mizuno, Tsunefumi and Muleri, Fabio and Ng, C.-Y. and O’Dell, Stephen L. and Omodei, Nicola and Oppedisano, Chiara and Papitto, Alessandro and Pavlov, George G. and Peirson, Abel L. and Perri, Matteo and Pesce-Rollins, Melissa and Petrucci, Pierre-Olivier and Pilia, Maura and Possenti, Andrea and Puccetti, Simonetta and Ramsey, Brian D. and Rankin, John and Ratheesh, Ajay and Romani, Roger W. and Sgrò, Carmelo and Slane, Patrick and Soffitta, Paolo and Spandre, Gloria and Tamagawa, Toru and Tavecchio, Fabrizio and Taverna, Roberto and Tawara, Yuzuru and Tennant, Allyn F. and Thomas, Nicholas E. and Tombesi, Francesco and Trois, Alessio and Turolla, Roberto and Vink, Jacco and Weisskopf, Martin C. and Wu, Kinwah and Xie, Fei and Schulz, Norbert S. and Chakrabarty, Deepto (2022) Observations of 4U 1626–67 with the Imaging X-Ray Polarimetry Explorer. Astrophysical Journal, 940 (1). Art. No. 70. ISSN 0004-637X. doi:10.3847/1538-4357/ac98c2.

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We present measurements of the polarization of X-rays in the 2–8 keV band from the pulsar in the ultracompact low-mass X-ray binary 4U 1626–67 using data from the Imaging X-Ray Polarimetry Explorer (IXPE). The 7.66 s pulsations were clearly detected throughout the IXPE observations as well as in the NICER soft X-ray observations, which we used as the basis for our timing analysis and to constrain the spectral shape over the 0.4–10 keV energy band. Chandra HETGS high-resolution X-ray spectra were also obtained near the times of the IXPE observations for firm spectral modeling. We found an upper limit on the pulse-averaged linear polarization of <4% (at 95% confidence). Similarly, there was no significant detection of polarized flux in pulse phase intervals when subdividing the bandpass by energy. However, spectropolarimetric modeling over the full bandpass in pulse phase intervals provided a marginal detection of polarization of the power-law spectral component at the 4.8% ± 2.3% level (90% confidence). We discuss the implications concerning the accretion geometry onto the pulsar, favoring two-component models of the pulsed emission.

Item Type:Article
Related URLs:
URLURL TypeDescription
Marshall, Herman L.0000-0002-6492-1293
Ng, Mason0000-0002-0940-6563
Rogantini, Daniele0000-0002-5359-9497
Heyl, Jeremy0000-0001-9739-367X
Tsygankov, Sergey S.0000-0002-9679-0793
Poutanen, Juri0000-0002-0983-0049
Costa, Enrico0000-0003-4925-8523
Zane, Silvia0000-0001-5326-880X
Malacaria, Christian0000-0002-0380-0041
Agudo, Iván0000-0002-3777-6182
Antonelli, Lucio A.0000-0002-5037-9034
Bachetti, Matteo0000-0002-4576-9337
Baldini, Luca0000-0002-9785-7726
Baumgartner, Wayne H.0000-0002-5106-0463
Bellazzini, Ronaldo0000-0002-2469-7063
Bianchi, Stefano0000-0002-4622-4240
Bongiorno, Stephen D.0000-0002-0901-2097
Bonino, Raffaella0000-0002-4264-1215
Brez, Alessandro0000-0002-9460-1821
Bucciantini, Niccolò0000-0002-8848-1392
Capitanio, Fiamma0000-0002-6384-3027
Castellano, Simone0000-0003-1111-4292
Cavazzuti, Elisabetta0000-0001-7150-9638
Ciprini, Stefano0000-0002-0712-2479
De Rosa, Alessandra0000-0001-5668-6863
Monte, Ettore Del0000-0002-3013-6334
Gesu, Laura Di0000-0002-5614-5028
Lalla, Niccolò Di0000-0002-7574-1298
Marco, Alessandro Di0000-0003-0331-3259
Donnarumma, Immacolata0000-0002-4700-4549
Doroshenko, Victor0000-0001-8162-1105
Dovčiak, Michal0000-0003-0079-1239
Ehlert, Steven R.0000-0003-4420-2838
Enoto, Teruaki0000-0003-1244-3100
Evangelista, Yuri0000-0001-6096-6710
Fabiani, Sergio0000-0003-1533-0283
Ferrazzoli, Riccardo0000-0003-1074-8605
García, Javier A.0000-0003-3828-2448
Gunji, Shuichi0000-0002-5881-2445
Hayashida, Kiyoshi0000-0002-0110-6136
Iwakiri, Wataru0000-0002-0207-9010
Jorstad, Svetlana G.0000-0001-9522-5453
Karas, Vladimir0000-0002-5760-0459
Kolodziejczak, Jeffery J.0000-0002-0110-6136
Krawczynski, Henric0000-0002-1084-6507
La Monaca, Fabio0000-0001-8916-4156
Latronico, Luca0000-0002-0984-1856
Liodakis, Ioannis0000-0001-9200-4006
Maldera, Simone0000-0002-0698-4421
Manfreda, Alberto0000-0002-0998-4953
Marin, Frédéric0000-0003-4952-0835
Marinucci, Andrea0000-0002-2055-4946
Marscher, Alan P.0000-0001-7396-3332
Matt, Giorgio0000-0002-2152-0916
Mizuno, Tsunefumi0000-0001-7263-0296
Muleri, Fabio0000-0003-3331-3794
Ng, C.-Y.0000-0002-5847-2612
O’Dell, Stephen L.0000-0002-1868-8056
Omodei, Nicola0000-0002-5448-7577
Oppedisano, Chiara0000-0001-6194-4601
Papitto, Alessandro0000-0001-6289-7413
Pavlov, George G.0000-0002-7481-5259
Peirson, Abel L.0000-0001-6292-1911
Perri, Matteo0000-0003-3613-4409
Pesce-Rollins, Melissa0000-0003-1790-8018
Petrucci, Pierre-Olivier0000-0001-6061-3480
Pilia, Maura0000-0001-7397-8091
Possenti, Andrea0000-0001-5902-3731
Puccetti, Simonetta0000-0002-2734-7835
Ramsey, Brian D.0000-0003-1548-1524
Rankin, John0000-0002-9774-0560
Ratheesh, Ajay0000-0003-0411-4243
Romani, Roger W.0000-0001-6711-3286
Sgrò, Carmelo0000-0001-5676-6214
Slane, Patrick0000-0002-6986-6756
Soffitta, Paolo0000-0001-8916-4156
Spandre, Gloria0000-0003-0802-3453
Tamagawa, Toru0000-0002-8801-6263
Tavecchio, Fabrizio0000-0003-0256-0995
Taverna, Roberto0000-0002-1768-618X
Tennant, Allyn F.0000-0002-9443-6774
Thomas, Nicholas E.0000-0003-0411-4606
Tombesi, Francesco0000-0002-6562-8654
Trois, Alessio0000-0002-3180-6002
Turolla, Roberto0000-0003-3977-8760
Vink, Jacco0000-0002-4708-4219
Weisskopf, Martin C.0000-0002-5270-4240
Wu, Kinwah0000-0002-7568-8765
Xie, Fei0000-0002-0105-5826
Schulz, Norbert S.0000-0002-0842-7792
Chakrabarty, Deepto0000-0001-8804-8946
Additional Information:IXPE is a joint US and Italian mission. The US contribution is supported by the National Aeronautics and Space Administration (NASA) and led and managed by its Marshall Space Flight Center (MSFC), with industry partner Ball Aerospace (contract NNM15AA18C). The Italian contribution is supported by the Italian Space Agency (Agenzia Spaziale Italiana, ASI) through contract ASI-OHBI-2017-12-I.0 and agreements ASI-INAF-2017-12-H0 and ASI-INFN-2017.13-H0, and its Space Science Data Center (SSDC) with agreements ASI-INAF-2022-14-HH.0 and ASI-INFN 2021-43-HH.0, and by Istituto Nazionale di Astrofisica (INAF) and Istituto Nazionale di Fisica Nucleare (INFN) in Italy. This research used data products provided by the IXPE Team (MSFC, SSDC, INAF, and INFN) and distributed with additional software tools by the High-energy Astrophysics Science Archive Research Center (HEASARC), at NASA Goddard Space Flight Center (GSFC). Funding for this work was provided in part by contract 80MSFC17C0012 from the MSFC to MIT in support of the IXPE project. Support for this work was provided in part by NASA through the Smithsonian Astrophysical Observatory (SAO) contract SV3-73016 to MIT for support of the Chandra X-Ray Center, which is operated by SAO for and on behalf of NASA under contract NAS8-03060. M.N. also acknowledges support from the NASA NICER program under detector team grant 80NSSC19K1287 and guest observer grant 80NSSC22K1350. S.S.T. and J.P. were supported by Russian Science Foundation grant 20-12-00364 and Academy of Finland grants 333112, 349144, 349373, and 349906. We thank K. C. Gendreau and Z. Arzoumanian for their help in arranging coordinated NICER scheduling of the observations.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Agenzia Spaziale Italiana (ASI)ASI-OHBI-2017-12-I.0
Agenzia Spaziale Italiana (ASI)ASI-INAF-2017-12-H0
Agenzia Spaziale Italiana (ASI)ASI-INFN-2017.13-H0
Agenzia Spaziale Italiana (ASI)ASI-INAF-2022-14-HH.0
Agenzia Spaziale Italiana (ASI)ASI-INFN 2021-43-HH.0
Istituto Nazionale di Fisica Nucleare (INFN)UNSPECIFIED
Smithsonian Astrophysical ObservatorySV3-73016
Russian Science Foundation20-12-00364
Academy of Finland333112
Academy of Finland349144
Academy of Finland349373
Academy of Finland349906
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Issue or Number:1
Record Number:CaltechAUTHORS:20230103-818063100.52
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:118642
Deposited By: Research Services Depository
Deposited On:30 Jan 2023 21:22
Last Modified:30 Jan 2023 21:22

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