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Global e-VLBI observations of the gamma-ray narrow line Seyfert 1 PMN J0948+0022

journal contribution
posted on 2023-05-17, 06:03 authored by Giroletti, M, Paragi, Z, Bignall, H, Doi, A, Foschini, L, Gabanyi, KE, Reynolds, C, Blanchard, J, Campbell, RM, Colomer, F, Hong, X, Kadler, M, Kino, M, van Langevelde, HJ, Nagai, H, Phillips, C, Sekido, M, Szomoru, A, Tzioumis, AK
Context. There is growing evidence of relativistic jets in radio-loud narrow-line Seyfert 1 (RL-NLS1) galaxies. Aims. We constrain the observational properties of the radio emission in the first RL-NLS1 galaxy ever detected in gamma-rays, PMN J0948+0022, i.e., its flux density and structure in both total intensity and polarization, its compactness, and variability. Methods. We performed three real-time e-VLBI observations of PMN J0948+0022 at 22 GHz, using a global array including telescopes in Europe, East Asia, and Australia. These are the first e-VLBI science observations ever carried out with a global array, reaching a maximum baseline length of 12 458 km. The observations were part of a large multiwavelength campaign in 2009. Results. The source is detected at all three epochs. The structure is dominated by a bright component, more compact than 55 ¥ìas, with a fainter component at a position angle ¥è ¡­ 35◦. Relativistic beaming is required by the observed brightness temperature of 3.4 ¡¿ 1011 K. Polarization is detected at a level of about 1%. Conclusions. The parameters derived by the VLBI observations, in addition to the broad-band properties, confirm that PMN J0948+0022 is similar to flat spectrum radio quasars. Global e-VLBI is a reliable and promising technique for future studies.

History

Publication title

Astronomy and Astrophysics: A European Journal

Volume

528

Issue

Apr

Pagination

EJ

ISSN

0004-6361

Department/School

School of Natural Sciences

Publisher

E D P Sciences

Place of publication

7, Ave Du Hoggar, Parc D Activites Courtaboeuf, Bp 112, Les Ulis Cedexa, France, F-91944

Rights statement

Copyright © EDP Sciences, 2011

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the physical sciences

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