Hubble Study of the Proper Motion of HST-1 in the Jet of M87

Fuente: arXiv
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Autores principales: Thimmappa, Rameshan, Neilsen, Joey, Haggard, Daryl, Nowak, Michael A., Stawarz, Łukasz
Formato: Preprint
Publicado: 2026
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author Thimmappa, Rameshan
Neilsen, Joey
Haggard, Daryl
Nowak, Michael A.
Stawarz, Łukasz
author_facet Thimmappa, Rameshan
Neilsen, Joey
Haggard, Daryl
Nowak, Michael A.
Stawarz, Łukasz
contents 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 \citep{Thimmappa24} reveals a correlation between the X-ray flux of HST-1 and its separation from the core. This correlation likely arises from moving shocks in the jet, allowing measurement of the internal structure of HST-1 in the X-ray band. To follow up on these results, we use observations from the {\it Hubble} Space Telescope Advanced Camera for Surveys HRC/WFC/SBC channel and the Wide Field Camera 3 (WFC3)'s UVIS to analyze the image and flux variability of HST-1. Our analysis includes 245 ACS and 120 WFC3 observations from 2002-2022, with a total exposure time of $\sim345$ ks. We study the brightness profile of the optical jet and measure the relative separation between the core and HST-1 for comparison to the X-ray. We find that the X-ray and the UV/optical emission could arise from physically distinct regions. The measured proper motion of the knot HST-1 is 1.04$\pm$0.04 c from 2002-2005 and around 2.1$\pm$0.05 c from 2005-2022. We discuss the acceleration of the jet and the flaring synchrotron emission from HST-1 from optical to X-rays.
format Preprint
id arxiv_https___arxiv_org_abs_2601_18893
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Hubble Study of the Proper Motion of HST-1 in the Jet of M87
Thimmappa, Rameshan
Neilsen, Joey
Haggard, Daryl
Nowak, Michael A.
Stawarz, Łukasz
Astrophysics of Galaxies
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 \citep{Thimmappa24} reveals a correlation between the X-ray flux of HST-1 and its separation from the core. This correlation likely arises from moving shocks in the jet, allowing measurement of the internal structure of HST-1 in the X-ray band. To follow up on these results, we use observations from the {\it Hubble} Space Telescope Advanced Camera for Surveys HRC/WFC/SBC channel and the Wide Field Camera 3 (WFC3)'s UVIS to analyze the image and flux variability of HST-1. Our analysis includes 245 ACS and 120 WFC3 observations from 2002-2022, with a total exposure time of $\sim345$ ks. We study the brightness profile of the optical jet and measure the relative separation between the core and HST-1 for comparison to the X-ray. We find that the X-ray and the UV/optical emission could arise from physically distinct regions. The measured proper motion of the knot HST-1 is 1.04$\pm$0.04 c from 2002-2005 and around 2.1$\pm$0.05 c from 2005-2022. We discuss the acceleration of the jet and the flaring synchrotron emission from HST-1 from optical to X-rays.
title Hubble Study of the Proper Motion of HST-1 in the Jet of M87
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2601.18893