Large Quasar Groups
Large quasar groups (LQGs) form some of the
largest structures in the universe, spanning over 100 Mpc. They are so
large that they probably have not been virialized. One LQG at
1.2<z<1.4, discovered and explored by Roger Clowes and Luis
Campusano and collaborators in the 1990s, has become a focus of a
series
of multi-wavelength investigations ranging from the far ultraviolet to
the near infrared. I am part of a research group which has
published a number of papers and has a range of active observing
proposals:
Selected Refereed Publications
Clowes, R.G. & Campusano, L.E. 1991,
MNRAS, 249, 218, "A
100-200 MPC group of quasars"
Clowes,
R.G. & Campusano, L.E. 1994,
MNRAS, 266, 317, "Observations
of Quasars in ESO / SERC Field 927"
Graham,
M.J., Clowes, R.G. & Campusano, L.E. 1994,
MNRAS, 266, 317, "Finding
Quasar Superstructures"
Clowes,
R.G., Campusano,
L.E. & Graham, M.J.
1999,
MNRAS, 309, 48, "
Further observations of quasars in ESO/SERC field 927"
Haines,
C.P., Clowes, R.G., Campusano,
L.E. & Adamson, A.J. 2001,
MNRAS, 323, 688, "The
galaxy environment of a quasar at z = 1.226: a possible cluster merger"
Söchting,
I.K., Clowes, R.G. & Campusano, L.E. 2002,
MNRAS, 331, 569, "Quasar
environment in the context of large-scale structure at z~0.3"
Williger,
G.M., Clowes, R.G., Campusano,
L.E. & Graham, M.J.
2002,
ApJ, 578, 708, "Large-Scale
Structure at z = 1.2 Outlined by Mg II Absorbers"
Söchting,
I.K., Clowes, R.G. & Campusano, L.E. 2004,
MNRAS, 347, 1241, "Relation
of radio-quiet quasars to galaxy clusters at z < 0.3"
Haines,
C.P., Clowes, R.G. & Campusano,
L.E. 2004,
A&A, 421, 157, "Detection
of 20-30 h-1 Mpc-scale galaxy structures embedded in 100 h-1
Mpc-scale structures of quasars and MgII absorbers at z>0.8 and
z<1.2"
Söchting,
I.K., Campusano,
L.E., Haines,
C.P., Clowes,
R.G., Williger,
G.M.,
Graham,
M.J., Valls-Gabaud, D., Kuhn, O. 2007, "Spectroscopic
pencil beam exploration
of a z~0.8 large-scale structure", MNRAS, submitted
Selected Recent Observing Programs
Williger, G.M., Davé, R., Clowes, R.G., Graham, M.G., Haines,
C.P., Liske, J. \& Campusano, L.E., 2003,
HST Cycle 12 program 9887, 27 orbits with STIS, NICMOS and ACS, "A
test of the foreground proximity effect at z=1.2"
Status: HST data all taken, being analysed; NOAO KPNO 4m IR
spectroscopy clouded out Feb 2004;
2 nights Mar 2005
Williger,
G.M., Campusano,
L.E., Clowes,
R.G., Valls-Gabaud, D., Davé,
R., Söchting,
I.K., Haines, C.P.
& Graham, M.G.,
2004, GALEX Cycle 1 program, 60 ksec, "Galaxies and quasars in the
largest structures at z~1"
Status: data ~90% taken, being analysed
Campusano,
L.E., Lopez, S., Haines, C.P. \& Williger, G.M., 2004,
ESO Cycle 74 program, VLT/UVES+NTT/SOFI, 31 hours, "Determining the
bias between galaxies and CIV (and MgII) absorbers at z=1.2"
Status: data all taken, being analysed
Kuhn, O., Clowes, R. G., Söchting,
I.K., 2004,
UKIRT UFTI imaging of Q1047+050
(z=1.215),
K 2.0 hrs, J 4.5 hrs
Status: data all taken, being analysed
Valls-Gabaud,
D., Clowes,
R.G., Haines,
C.P., Williger,
G.M. & Campusano,
L.E., 2004, CFHT/MegaCam
2007a program, 7 hours in rz, "Large-scale galaxy sheets at z=0.8 and
z=1.2 and the quasar-galaxy relation toward a Large Quasar Group"
Status: data not taken yet
Williger,
G. et al., Feb/Dec 2004, Apache Point 3.5m Fabry-Perot
imaging of Q1044+059 (z=1.23) tuned
to [OII] at z=1.23 plus I-band, ~3 hours narrowband
Status: data all taken, being analysed
Campusano,
L.E. (PI), Söchting,
I.K. (lead UK scientist), Williger, G.M. (lead US scientist), Haines,
C.P., Clowes,
R.G., Graham, M., Valls-Gabaud, D., 2005,
Gemini-South/GMOS 2005a program, 38 hours, "The Galaxy Population
Around a Possibly Forming Cluster at z~1.2"
Status: Galaxy overdensity found at z~0.8, See Söchting
et al. 2005,
BAAS, 207, 112.03
Clowes,
R. G., Kuhn,
O., Söchting, I.K.,
Jan 2005, CTIO 4m Mosaic-II VRIz, 6 half nights
Status: data taken, being reduced and analysed by Clowes and
collaborators
Davé, R et al., Jan
2007, Steward Obs. Bok 2.3m+90prime for gi imaging of
GALEX fields, 4 nights (~2 useful)
Status: data being reduced
Haberzettl, L. et al., Feb-Mar
2007, KPNO 2.1m+FLAMINGOS for JK imaging
of GALEX fields, 18.5 nights
Status: data being reduced
Davé, R et al., Feb 2007,
Magellan 6.5m+IMACS, multi-slit spectroscopy
of LBGs in GALEX north field, 2 nights
Status: data being reduced
Image of part of Large Quasar Group
(16 Mb):
CTIO
Big Throughput Camera image (30x30 arcmin) courtesy of Chris Haines, N
up, E
right
Selected Popular Articles
New York
Times
BBC piece
Der
Spiegel