The Cosmological Evolution Survey (COSMOS) is an astronomical survey designed to probe the formation and evolution of galaxies as a function of both cosmic time (redshift) and the local galaxy environment. The survey covers a 2 square degree equatorial field with imaging by most of the major space-based telescopes and a number of large ground based telescopes, with many ongoing surveys. Over 2 million galaxies are detected, spanning 75% of the age of the Universe. The COSMOS survey involves more than 100 scientists in a dozen countries.
For website content comments or questions please contact Jacinta Delhaize - jacinta [at] phy.hr
A new paper by COSMOS member Andreas Faisst and team shows how to use Spitzer colors to derive emission line properties of 3 < z < 6 galaxies. Optical emission lines at z > 4 cannot be measured spectroscopically with current facilities. Since emission lines "contaminate" the Spitzer 3.6um and 4.5um channels, these can be used to estimate optical line emission without the need of spectra. The study of emission lines provides important information about galaxy formation in the early universe and also provides a sample of galaxies for future JWST follow-up. The ApJ paper is in print and can be retrieved here: http://stacks.iop.org/0004-637X/821/122
The COSMOS2015 catalogue combines the >30 band photometry and SED fits (photometric redshifts, stellar masses, SFRs, etc) of half a million sources up to z=6 spread over the 2 square-degrees of COSMOS.
In particular, it uses the new UltraVISTA images, as well as the Spitzer SPLASH photometry!
The paper by Laigle et al. (2016) explaining the catalog can be found on the arXiv now: http://arxiv.org/abs/1604.02350
The catalog can be downloaded via anonymous FTP.
Image: A comparison of spectroscopic and photometric redshifts of COSMOS2015 galaxies. The dashed and dashed-dot lines show zp=zs±0.05(1+zs) and zp=zs±0.15(1+zs), respectively. From Laigle et al (2016) Figure 12.
UltraVISTA is an Ultra Deep, near-infrared survey with ESO's VISTA surveys telescope. Over the course of 5 years, UltraVISTA is imaging the COSMOS field in 5 bands (Y, J, H, Ks, NB118) and therefore represents a key survey on COSMOS. The 3rd data release (DR3) is now public and can be downloaded on the ESO archive web-page.
The principal difference with respect to the DR2 release is a substantial increase in exposure time in all five bands (by a factor of 1.7-4.6) in the four "ultra-deep stripes" regions, corresponding to an increase in depth of 0.4 to 0.8 magnitudes. The DR3 final magnitudes are 24.8, 24.5, 24.1, 23.8 mag in the deep stripes and 25.7, 25.4, 25.1, 24.9 mag in the ultra-deep stripes for Y, J, H, and Ks band, respectively. The magnitude limit for the narrow-band NB118 observation (only in ultra-deep stripe) is 24.1 magnitudes (AB).
Above: Color composite of the UltraVISTA field on COSMOS.