X-Ray Polarization of BL Lacertae in Outburst

DOI: 
10.3847/2041-8213/acd242
Publication date: 
13/05/2023
Main author: 
Peirson, Abel L.
IAA authors: 
Agudo, Iván;Aceituno, Francisco José;Bernardos, Maria I.;Bonnoli, Giacomo;Casanova, Víctor;García-Comas, Maya;Agís-González, Beatriz;Husillos, César;Sota, Alfredo;Escudero, Juan
Authors: 
Peirson, Abel L.;Negro, Michela;Liodakis, Ioannis;Middei, Riccardo;Kim, Dawoon E.;Marscher, Alan P.;Marshall, Herman L.;Pacciani, Luigi;Romani, Roger W.;Wu, Kinwah;Di Marco, Alessandro;Di Lalla, Niccoló;Omodei, Nicola;Jorstad, Svetlana G.;Agudo, Iván;Kouch, Pouya M.;Lindfors, Elina;Aceituno, Francisco José;Bernardos, Maria I.;Bonnoli, Giacomo;Casanova, Víctor;García-Comas, Maya;Agís-González, Beatriz;Husillos, César;Marchini, Alessandro;Sota, Alfredo;Casadio, Carolina;Escudero, Juan;Myserlis, Ioannis;Sievers, Albrecht;Gurwell, Mark;Rao, Ramprasad;Imazawa, Ryo;Sasada, Mahito;Fukazawa, Yasushi;Kawabata, Koji S.;Uemura, Makoto;Mizuno, Tsunefumi;Nakaoka, Tatsuya;Akitaya, Hiroshi;Cheong, Yeon;Jeong, Hyeon-Woo;Kang, Sincheol;Kim, Sang-Hyun;Lee, Sang-Sung;Angelakis, Emmanouil;Kraus, Alexander;Cibrario, Nicoló;Donnarumma, Immacolata;Poutanen, Juri;Tavecchio, Fabrizio;Antonelli, Lucio A.;Bachetti, Matteo;Baldini, Luca;Baumgartner, Wayne H.;Bellazzini, Ronaldo;Bianchi, Stefano;Bongiorno, Stephen D.;Bonino, Raffaella;Brez, Alessandro;Bucciantini, Niccoló;Capitanio, Fiamma;Castellano, Simone;Cavazzuti, Elisabetta;Chen, Chien-Ting;Ciprini, Stefano;Costa, Enrico;De Rosa, Alessandra;Del Monte, Ettore;Di Gesu, Laura;Doroshenko, Victor;Dovčiak, Michal;Ehlert, Steven R.;Enoto, Teruaki;Evangelista, Yuri;Fabiani, Sergio;Ferrazzoli, Riccardo;Garcia, Javier A.;Gunji, Shuichi;Hayashida, Kiyoshi;Heyl, Jeremy;Iwakiri, Wataru;Kaaret, Philip;Karas, Vladimir;Kitaguchi, Takao;Kolodziejczak, Jeffery J.;Krawczynski, Henric;La Monaca, Fabio;Latronico, Luca;Madejski, Grzegorz;Maldera, Simone;Manfreda, Alberto;Marin, Frédéric;Marinucci, Andrea;Massaro, Francesco;Matt, Giorgio;Mitsuishi, Ikuyuki;Muleri, Fabio;Ng, C. -Y.;O'Dell, Stephen L.;Oppedisano, Chiara;Papitto, Alessandro;Pavlov, George G.;Perri, Matteo;Pesce-Rollins, Melissa;Petrucci, Pierre-Olivier;Pilia, Maura;Possenti, Andrea;Puccetti, Simonetta;Ramsey, Brian D.;Rankin, John;Ratheesh, Ajay;Roberts, Oliver J.;Sgró, Carmelo;Slane, Patrick;Soffitta, Paolo;Spandre, Gloria;Swartz, Douglas A.;Tamagawa, Toru;Taverna, Roberto;Tawara, Yuzuru;Tennant, Allyn F.;Thomas, Nicholas E.;Tombesi, Francesco;Trois, Alessio;Tsygankov, Sergey;Turolla, Roberto;Vink, Jacco;Weisskopf, Martin C.;Xie, Fei;Zane, Silvia
Journal: 
The Astrophysical Journal
Publication type: 
Article
Volume: 
948
Pages: 
L25
Abstract: 
We report the first &gt;99% confidence detection of X-ray polarization in BL Lacertae. During a recent X-ray/γ-ray outburst, a 287 ks observation (2022 November 27-30) was taken using the Imaging X-ray Polarimetry Explorer (IXPE), together with contemporaneous multiwavelength observations from the Neil Gehrels Swift observatory and XMM-Newton in soft X-rays (0.3-10 keV), NuSTAR in hard X-rays (3-70 keV), and optical polarization from the Calar Alto and Perkins Telescope observatories. Our contemporaneous X-ray data suggest that the IXPE energy band is at the crossover between the low- and high-frequency blazar emission humps. The source displays significant variability during the observation, and we measure polarization in three separate time bins. Contemporaneous X-ray spectra allow us to determine the relative contribution from each emission hump. We find &gt;99% confidence X-ray polarization ${{\rm{\Pi }}}_{2\mbox{--}4\mathrm{keV}}={21.7}_{-7.9}^{+5.6} \% $ and electric vector polarization angle ψ <SUB>2-4keV</SUB> = -28.°7 ± 8.°7 in the time bin with highest estimated synchrotron flux contribution. We discuss possible implications of our observations, including previous IXPE BL Lacertae pointings, tentatively concluding that synchrotron self-Compton emission dominates over hadronic emission processes during the observed epochs.
Database: 
ADS
URL: 
https://ui.adsabs.harvard.edu/#abs/2023ApJ...948L..25P/abstract
ADS Bibcode: 
2023ApJ...948L..25P
Keywords: 
Astrophysical black holes;Black hole physics;Supermassive black holes;Active galactic nuclei;Active galaxies;Jets;Galaxy jets;Relativistic jets;Compact radiation sources;X-ray astronomy;98;159;1663;16;17;870;601;1390;289;1810;Astrophysics - High Energy Astrophysical Phenomena;Astrophysics - Astrophysics of Galaxies