Oguri, Masamune, Hennawi, Joseph F., Gladders, Michael D., Dahle, Haakon, Natarajan, Priyamvada, Dalal, Neal, ...
We derive radial mass profiles of four strong lensing selected clusters which show prominent giant arcs (Abell 1703, SDSS J1446+3032, SDSS J1531+3414, and SDSS J2111-0115), by combining detailed...
Riemer-Sorensen, Signe, Paraficz, Danka, Ferreira, Desiree Della Monica, Pedersen, Kristian, Limousin, Marceau, Dahle, Haakon
There is a long-standing discrepancy between galaxy cluster masses determined from X-ray and gravitational lensing observations of which Abell 1689 is a well-studied example. In this work we take...
Searching for decaying axion-like dark matter from clusters of galaxies (2007)
Riemer-Sorensen, Signe, Zioutas, Konstantin, Hansen, Steen H., Pedersen, Kristian, Dahle, Haakon, Liolios, Anastasios
We consider the possibility of constraining the lifetime of radiatively decaying dark matter particles in clusters of galaxies inspired from generic axions of the Kaluza-Klein type. Such axions have...
Riemer-Sorensen, Signe, Pedersen, Kristian, Hansen, Steen H., Dahle, Haakon
Gravitational lensing observations of galaxy clusters have identified dark matter ``blobs'' with remarkably low baryonic content. We use such a system to probe the particle nature of dark matter with...
Pedersen, Kristian, Dahle, Haakon
The main uncertainty in current determinations of the power spectrum normalization, sigma_8, from abundances of X-ray luminous galaxy clusters arises from the calibration of the mass-temperature...
The Shear TEsting Programme 1: Weak lensing analysis of simulated ground-based observations (2005)
Heymans, Catherine, Van Waerbeke, Ludovic, Bacon, David, Berge, Joel, Bernstein, Gary, Bertin, Emmanuel, ...
The Shear TEsting Programme, STEP, is a collaborative project to improve the accuracy and reliability of all weak lensing measurements in preparation for the next generation of wide-field surveys. In...
Probing galaxy density profiles with future supernova surveys (2004)
Mortsell, Edvard, Dahle, Haakon, Hannestad, Steen
In this paper we discuss the possibility to measure the Hubble parameter and the slope of galaxy density profiles using future supernova data. With future supernova surveys such as SNAP, large...
Optical Photometry of GRB 021004: The First Month (2002)
Holland, Stephen T., Weidinger, Michael, Fynbo, Johan P. U., Gorosabel, Javier, Hjorth, Jens, Pedersen, Kristian, ...
We present U,B,V,R_C,and I_C photometry of the optical afterglow of the gamma-ray burst GRB 021004 taken at the Nordic Optical Telescope between approximately eight hours and 30 days after the burst....
The Density Profile of Cluster-scale Dark Matter Halos (2002)
Dahle, Haakon, Hannestad, Steen, Sommer-Larsen, Jesper
We measure the average gravitational shear profile of 6 massive clusters (M_vir ~ 10^15 M_sun) at z=0.3 out to a radius ~2h^-1 Mpc. The measurements are fitted to a generalized NFW-like halo model...
Irgens, Ragnvald J., Lilje, Per B., Dahle, Haakon, Maddox, S. J.
Dynamic velocity dispersion and mass estimates are given for a sample of five X-ray luminous rich clusters of galaxies at intermediate redshifts (z~0.3) drawn from a sample of 39 clusters for which...
Hudson, Michael J., Gwyn, Stephen D. J., Dahle, Haakon, Kaiser, Nick
A tangential distortion of background source galaxies around foreground lens galaxies in the Hubble Deep Field is detected at the 99.3% confidence level. An important element of our analysis is the...