2023A&A...671A..43C


Query : 2023A&A...671A..43C

2023A&A...671A..43C - Astronomy and Astrophysics, volume 671A, 43 (2023/3-1)

PKS 1413+135: OH and H I at z = 0.247 with MeerKAT.

COMBES F., GUPTA N., MULLER S., BALASHEV S., DEKA P.P., EMIG K.L., KLOCKNER H.-R., KLUTSE D., KNOWLES K., MOHAPATRA A., MOMJIAN E., NOTERDAEME P., PETITJEAN P., SALAS P., SRIANAND R. and WAGENVELD J.D.

Abstract (from CDS):

The BL Lac object PKS 1413+135 was observed by the Large Survey Project MeerKAT Absorption Line Survey (MALS) in the L-band, at 1139 MHz and 1293-1379 MHz, targeting the H I and OH lines in absorption at z = 0.24671. The radio continuum might come from the nucleus of the absorbing galaxy or from a background object at redshift lower than 0.5, as suggested by the absence of gravitational images. The H I absorption line is detected at a high signal-to-noise ratio, with a narrow central component, and with a red wing, confirming previous results. The OH 1720 MHz line is clearly detected in (maser) emission, peaking at a velocity shifted by -10 to -15 km s–1 with respect to the H I peak. The 1612 MHz line is lost due to radio frequency interference. The OH 1667 MHz main line is tentatively detected in absorption, but not the 1665 MHz line. Over 30 years a high variability is observed in optical depths, due to the rapid changes of the line of sight caused by the superluminal motions of the radio knots. The H I line has varied by 20% in depth, while the OH-1720 MHz depth has varied by a factor of ∼3. The position of the central velocity and the widths also varied. The absorbing galaxy is an early-type spiral (maybe S0) seen edge-on, with a prominent dust lane, covering the whole disk. Given the measured mass concentration and the radio continuum size at centimeter wavelengths (100 mas corresponding to 400 pc at z = 0.25), the width of the absorption lines from the nuclear regions are expected up to 250 km s–1. The narrowness of the observed lines (< 15 km s–1) suggests that the absorption comes from an outer gas ring, as frequently observed in S0 galaxies. The millimetric lines are even narrower (< 1 km s–1), which corresponds to the continuum size restricted to the core. The radio core is covered by individual 1 pc molecular clouds, whose column density is a few 1022 cm–2, which is compatible with the gas screen detected in X-rays.

Abstract Copyright: © The Authors 2023

Journal keyword(s): BL Lacertae objects: individual: PKS1413+135 - galaxies: general - galaxies: kinematics and dynamics - quasars: absorption lines - galaxies: ISM

VizieR on-line data: <Available at CDS (J/A+A/671/A43): hi-all.dat oh-main.dat oh-1720.dat>

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4351 2
2 ICRF J134733.3+121724 Sy2 13 47 33.36161873 +12 17 24.2398927   19.28 18.44 15.718   ~ 597 3
3 ICRF J141558.8+132023 Sy2 14 15 58.81751033 +13 20 23.7128587   21.055 20.000 18.461   ~ 440 1
4 QSO B1830-211 Bla 18 33 39.9399138048 -21 03 39.368838780     18.70 21   ~ 676 1
5 ICRF J193925.0-634245 Sy2 19 39 25.0245304992 -63 42 45.640373400   18.87 18.37 17.64   ~ 1236 1

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