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Title: SPATIALLY RESOLVED HCN ABSORPTION FEATURES IN THE CIRCUMNUCLEAR REGION OF NGC 1052

Abstract

We present the first VLBI detection of HCN molecular absorption in the nearby active galactic nucleus NGC 1052. Utilizing the 1 mas resolution achieved by the Korean VLBI Network, we have spatially resolved the HCN absorption against a double-sided nuclear jet structure. Two velocity features of HCN absorption are detected significantly at the radial velocity of 1656 and 1719 km s{sup −1}, redshifted by 149 and 212 km s{sup −1} with respect to the systemic velocity of the galaxy. The column density of the HCN molecule is estimated to be 10{sup 15}–10{sup 16} cm{sup −2}, assuming an excitation temperature of 100–230 K. The absorption features show high optical depth localized on the receding jet side, where the free–free absorption occurred due to the circumnuclear torus. The size of the foreground absorbing molecular gas is estimated to be on approximately one-parsec scales, which agrees well with the approximate size of the circumnuclear torus. HCN absorbing gas is likely to be several clumps smaller than 0.1 pc inside the circumnuclear torus. The redshifted velocities of the HCN absorption features imply that HCN absorbing gas traces ongoing infall motion inside the circumnuclear torus onto the central engine.

Authors:
 [1]; ; ; ; ; ; ; ;  [2];  [3]
  1. Mizusawa VLBI Observatory, National Astronomical Observatory of Japan, 2-12 Hoshigaoka-cho, Mizusawa-ku, Oshu, Iwate 023-0861 (Japan)
  2. Korea Astronomy and Space Science Institute, 776 Daedeok-daero, Yuseong, Daejeon 34055 (Korea, Republic of)
  3. Joint ALMA Observatory, Alonso de Cordova 3107 Vitacura, Santiago 763 0355 (Chile)
Publication Date:
OSTI Identifier:
22654201
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 830; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; APPROXIMATIONS; DENSITY; DETECTION; EXCITATION; GALAXIES; GALAXY NUCLEI; HYDROCYANIC ACID; RADIAL VELOCITY; RED SHIFT; RESOLUTION

Citation Formats

Sawada-Satoh, Satoko, Roh, Duk-Gyoo, Oh, Se-Jin, Lee, Sang-Sung, Byun, Do-Young, Yeom, Jae-Hwan, Jung, Dong-Kyu, Kim, Hyo-Ryoung, Hwang, Ju-Yeon, and Kameno, Seiji, E-mail: satoko.ss@nao.ac.jp, E-mail: sss@mx.ibaraki.ac.jp. SPATIALLY RESOLVED HCN ABSORPTION FEATURES IN THE CIRCUMNUCLEAR REGION OF NGC 1052. United States: N. p., 2016. Web. doi:10.3847/2041-8205/830/1/L3.
Sawada-Satoh, Satoko, Roh, Duk-Gyoo, Oh, Se-Jin, Lee, Sang-Sung, Byun, Do-Young, Yeom, Jae-Hwan, Jung, Dong-Kyu, Kim, Hyo-Ryoung, Hwang, Ju-Yeon, & Kameno, Seiji, E-mail: satoko.ss@nao.ac.jp, E-mail: sss@mx.ibaraki.ac.jp. SPATIALLY RESOLVED HCN ABSORPTION FEATURES IN THE CIRCUMNUCLEAR REGION OF NGC 1052. United States. doi:10.3847/2041-8205/830/1/L3.
Sawada-Satoh, Satoko, Roh, Duk-Gyoo, Oh, Se-Jin, Lee, Sang-Sung, Byun, Do-Young, Yeom, Jae-Hwan, Jung, Dong-Kyu, Kim, Hyo-Ryoung, Hwang, Ju-Yeon, and Kameno, Seiji, E-mail: satoko.ss@nao.ac.jp, E-mail: sss@mx.ibaraki.ac.jp. Mon . "SPATIALLY RESOLVED HCN ABSORPTION FEATURES IN THE CIRCUMNUCLEAR REGION OF NGC 1052". United States. doi:10.3847/2041-8205/830/1/L3.
@article{osti_22654201,
title = {SPATIALLY RESOLVED HCN ABSORPTION FEATURES IN THE CIRCUMNUCLEAR REGION OF NGC 1052},
author = {Sawada-Satoh, Satoko and Roh, Duk-Gyoo and Oh, Se-Jin and Lee, Sang-Sung and Byun, Do-Young and Yeom, Jae-Hwan and Jung, Dong-Kyu and Kim, Hyo-Ryoung and Hwang, Ju-Yeon and Kameno, Seiji, E-mail: satoko.ss@nao.ac.jp, E-mail: sss@mx.ibaraki.ac.jp},
abstractNote = {We present the first VLBI detection of HCN molecular absorption in the nearby active galactic nucleus NGC 1052. Utilizing the 1 mas resolution achieved by the Korean VLBI Network, we have spatially resolved the HCN absorption against a double-sided nuclear jet structure. Two velocity features of HCN absorption are detected significantly at the radial velocity of 1656 and 1719 km s{sup −1}, redshifted by 149 and 212 km s{sup −1} with respect to the systemic velocity of the galaxy. The column density of the HCN molecule is estimated to be 10{sup 15}–10{sup 16} cm{sup −2}, assuming an excitation temperature of 100–230 K. The absorption features show high optical depth localized on the receding jet side, where the free–free absorption occurred due to the circumnuclear torus. The size of the foreground absorbing molecular gas is estimated to be on approximately one-parsec scales, which agrees well with the approximate size of the circumnuclear torus. HCN absorbing gas is likely to be several clumps smaller than 0.1 pc inside the circumnuclear torus. The redshifted velocities of the HCN absorption features imply that HCN absorbing gas traces ongoing infall motion inside the circumnuclear torus onto the central engine.},
doi = {10.3847/2041-8205/830/1/L3},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 830,
place = {United States},
year = {Mon Oct 10 00:00:00 EDT 2016},
month = {Mon Oct 10 00:00:00 EDT 2016}
}