Bibcode
DOI
Colley, Wesley N.; Schild, Rudolph E.; Abajas, Cristina; Alcalde, David; Aslan, Zeki; Bikmaev, Ilfan; Chavushyan, Vahram; Chinarro, Luis; Cournoyer, Jean-Philippe; Crowe, Richard; Dudinov, Vladimir; Evans, Anna Kathinka Dalland; Jeon, Young-Beom; Goicoechea, Luis J.; Golbasi, Orhan; Khamitov, Irek; Kjernsmo, Kjetil; Lee, Hyun Ju; Lee, Jonghwan; Lee, Ki Won; Lee, Myung Gyoon; Lopez-Cruz, Omar; Mediavilla, Evencio; Moffat, Anthony F. J.; Mujica, Raul; Ullan, Aurora; Muñoz, José; Oscoz, Alexander; Park, Myeong-Gu; Purves, Norman; Saanum, Oyvind; Sakhibullin, Nail; Serra-Ricart, Miquel; Sinelnikov, Igor; Stabell, Rolf; Stockton, Alan; Teuber, Jan; Thompson, Roy; Woo, Hwa-Sung; Zheleznyak, Alexander
Bibliographical reference
The Astrophysical Journal, Volume 587, Issue 1, pp. 71-79.
Advertised on:
4
2003
Journal
Citations
40
Refereed citations
29
Description
We report on an observing campaign in 2001 March to monitor the
brightness of the later arriving Q0957+561B image in order to compare
with the previously published brightness observations of the
(first-arriving) A image. The 12 participating observatories provided
3543 image frames, which we have analyzed for brightness fluctuations.
From our classical methods for time-delay determination, we find a
417.09+/-0.07 day time delay, which should be free of effects due to
incomplete sampling. During the campaign period, the quasar brightness
was relatively constant and only small fluctuations were found; we
compare the structure function for the new data with structure function
estimates for the 1995-1996 epoch and show that the structure function
during our observing interval is unusually depressed. We also examine
the data for any evidence of correlated fluctuations at zero lag. We
discuss the limits of our ability to measure the cosmological time delay
if the quasar's emitting surface is time resolved, as seems likely.