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We present a high resolution polarimetry and variability study of the M87 jet using VLA and HST data taken during 2002 to 2008. Both data-sets have an angular resolution as high as 0.06$"$, which is 2-3 times better than previous…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Sayali S Avachat , Eric S Perlman , William B Sparks , Mihai Cara , Frazer N Owen

During the last decade, M87's jet has been the site of an extraordinary variability event, with one knot (HST-1) increasing by over a factor 100 in brightness. Variability was also seen on timescales of months in the nuclear flux. Here we…

We present full-track high-resolution radio observations of the jet of the galaxy M87 at 8 and 15 GHz. These observations were taken over three consecutive days in May 2009 using the Very Long Baseline Array (VLBA), one antenna of the Very…

Astrophysics of Galaxies · Physics 2023-10-31 A. S. Nikonov , Y. Y. Kovalev , E. V. Kravchenko , I. N. Pashchenko , A. P. Lobanov

We discuss optical (HST/WFPC2 F555W) and radio (15 GHz VLA) polarimetry observations of the M87 jet taken during 1994-1995. Many knot regions are very highly polarized ($\sim 40-50%$, approaching the theoretical maximum for optically thin…

We present unprecedented high fidelity radio images of the M87 jet. We analyzed Jansky Very Large Array (VLA) broadband, full polarization, radio data from 4 to 18 GHz. The observations were taken with the most extended configuration (A…

We investigate the total flux density, spectral, polarization, and Faraday rotation variability of HST-1 in the M87 jet during the outburst from 2003 to 2007 through multi-epoch VLA observations at 8, 15, and 22 GHz. Contrary to the general…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Y. J. Chen , G. -Y. Zhao , Z. -Q. Shen

We present an overview of new HST imaging polarimetry of six nearby radio galaxies with optical jets. These observations triple the number of extragalactic jets with subarcsecond-resolution optical polarimetry. We discuss the polarization…

The radio galaxy M87 is well known for its jet, which features a series of bright knots observable from radio to X-ray wavelengths. We analyze the X-ray image and flux variability of the knot HST-1 in the jet. Our analysis includes all 112…

High Energy Astrophysical Phenomena · Physics 2024-05-03 Rameshan Thimmappa , Joey Neilsen , Daryl Haggard , Michael A. Nowak , Sera Markoff

We investigate the magnetic field configuration of the M87 jet at arc-second scales by using archival polarimetric VLA data at 8, 15, 22 and 43 GHz. By stacking images over three years in order to enhance the sensitivity, we reveal, for the…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-31 J. C. Algaba , K. Asada , M. Nakamura

Aims: We aim to constrain the structural variations within the HST-1 region downstream of the radio jet of M87, in general as well as in connection to the episodes of activity at very high energy (VHE). Methods: We analyzed and compared 26…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 M. Giroletti , K. Hada , G. Giovannini , C. Casadio , M. Beilicke , A. Cesarini , C. C. Cheung , A. Doi , H. Krawczynski , M. Kino , N. P. Lee , H. Nagai

The active galactic nucleus (AGN) within M87, a giant elliptical galaxy, is responsible for one of the closest kiloparsec-scale relativistic jet to Earth. We unearthed unpublished M87 polarization maps taken with the Faint Object Camera…

Astrophysics of Galaxies · Physics 2024-10-11 F. Marin , T. Barnouin , K. Wu , E. Lopez-Rodriguez

To obtain a better understanding of the location and mechanisms for the production of the gamma-ray emission in jets of AGN we present a detailed study of the HST-1 structure, 0.8 arcsec downstream the jet of M87, previously identified as a…

We present new ultraviolet photometry of the jet in M87 obtained from HST WFPC2 imaging. We combine these ultraviolet data with previously published photometry for the knots of the jet in radio, optical, and X-ray, and fit three theoretical…

Astrophysics · Physics 2009-11-10 C. Z. Waters , S. E. Zepf

The radio galaxy M87 is well known for its jet, which features a series of bright knots observable from radio to X-ray wavelengths. The most famous of these, HST-1, exhibits superluminal motion, and our analysis of {\it Chandra} data…

Astrophysics of Galaxies · Physics 2026-01-28 Rameshan Thimmappa , Joey Neilsen , Daryl Haggard , Michael A. Nowak , Łukasz Stawarz

Recent multi-wavelength observations of M87* \citep{2024A&A...692A.140A} revealed a high-energy $\gamma$-ray flare without a corresponding millimeter counterpart. We present a theoretical polarimetric study to evaluate the presence and…

The central radio source in M87 provides the best opportunity to study jet formation because it has a large angular size for the gravitational radius of the black hole and has a bright jet that is well resolved by VLBI observations. We…

High Energy Astrophysical Phenomena · Physics 2018-03-28 R. Craig Walker , Phillip E. Hardee , Frederick B. Davies , Chun Ly , William Junor

We reanalyze the deep Chandra observations of the M87 jet, first examined by Wilson & Yang (2002). By employing an analysis chain that includes image deconvolution, knots HST-1 and I are fully separated from adjacent emission. We find…

Astrophysics · Physics 2009-11-10 Eric S. Perlman , Andrew S. Wilson

We study the optical linear and circular polarisation in the optically-thin regime of the core and jet of M87. Observations were acquired two days before the Event Horizon Telescope (EHT) campaign in early April 2017. A high degree ($\sim…

Astrophysics of Galaxies · Physics 2020-06-17 A. Y. Fresco , J. A. Fernández-Ontiveros , M. A. Prieto , J. A. Acosta-Pulido , A. Merloni

We investigate the variability timescales in the jet of M87 with two goals. The first is to use the rise times and decay times in the radio, ultraviolet and X-ray lightcurves of HST-1 to constrain the source size and the energy loss…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 D. E. Harris , C. C. Cheung , Lukasz Stawarz , J. A. Biretta , E. S. Perlman

A previously inconspicuous knot in the M87 jet has undergone a dramatic outburst and now exceeds the nucleus in optical and X-ray luminosity. Monitoring of M87 with the Hubble Space Telescope and Chandra X-ray Observatory during 2002-2003,…

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