Issue |
A&A
Volume 491, Number 3, December I 2008
|
|
---|---|---|
Page(s) | 739 - 746 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:200810392 | |
Published online | 07 October 2008 |
Drastic changes in the molecular absorption at redshift z = 0.89 toward the quasar PKS 1830–211
1
Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), PO Box 23–141, Taipei, 106, Taiwan e-mail: muller@asiaa.sinica.edu.tw
2
Institut de Radio Astronomie Millimétrique (IRAM), 300 rue de la piscine, 38406 St Martin d'Hères, France
3
École Normale Supérieure/LERMA, 24 rue Lohmond, 75005 Paris, France
Received:
16
June
2008
Accepted:
24
September
2008
A 12 year-long monitoring of the absorption caused by a spiral galaxy
on the line of sight to the radio-loud gravitationally lensed quasar PKS 1830-211 reveals
spectacular changes in the HCO+ and HCN (2–1) line profiles. The depth of the absorption
toward the quasar NE image increased by a factor of ~ 3 in 1998–1999 and subsequently
decreased by a factor
6 between 2003 and 2006. These changes were echoed by similar
variations in the absorption line wings toward the SW image. Most likely, these variations
result from a motion of the quasar images with respect to the foreground galaxy,
which could be due to a sporadic ejection of bright plasmons by the background quasar.
VLBA observations have shown that the separation between the NE and SW images changed in 1997 by
as much as 0.2 mas within a few months. Assuming that motions of similar amplitude
occurred in 1999 and 2003, we argue that the clouds responsible for the NE absorption and
the broad wings of the SW absorption should be sparse and have characteristic sizes of
0.5–1 pc.
Key words: galaxies: quasars: individual: PKS 1830-211 / galaxies: quasars: absorption lines / galaxies: ISM / ISM: molecules
© ESO, 2008
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.