Current spotlights

Last week, we released the COSMOS2025 galaxy catalog from the COSMOS-Web survey, offering photometric and physical measurements for nearly 800,000 galaxies across 0.54 square degrees of sky — roughly the area covered by three full moons. This represents the largest and deepest survey of its kind to date and opens the door to a wealth of new discoveries about our Universe.

COSMOS-Web provides the largest view deep into the universe ever, and now all of its data are available publicly in an easily searchable format.

COSMOS-Web was the largest General Observer program selected for Cycle 1 of the James Webb Space Telescope (JWST). The survey mapped 0.54 square degrees of the sky (about the area of three full moons) with the Near Infrared Camera (NIRCam) and a 0.2 square degree area with the Mid Infrared Instrument (MIRI). The deep imaging comes with a catalog (the “COSMOS2025” catalog), which contains photometry, structural measurements, redshifts, and physical parameters for nearly 800,000 galaxies. Thanks to JWST imaging and previous COSMOS data, the catalog opens many unexplored scientific avenues.

Along with the data itself and three initial papers on the catalog, near infrared imaging, and mid infrared imaging, the data release so includes an interactive viewer where users can directly search images for specific objects or click on objects to see their properties. The COSMOS-Web images, catalog, and interactive viewer are available through the team’s data release website.

The first images from the largest program in the James Webb Space Telescope’s first year show many types of galaxies, including dazzling examples of spiral galaxies, gravitational lensing, and evidence of galaxy mergers. Scientists from the COSMOS-Web program released mosaic images taken in early January by JWST’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI).

COSMOS-Web aims to map the earliest structures of the universe and will create a wide and deep survey of up to 1 million galaxies. Over the course of 255 hours of observing time, COSMOS-Web will map 0.6 square degrees of the sky with NIRCam, roughly the size of three full moons, and 0.2 square degrees with MIRI.

• discover and characterize thousands of galaxies in the Epoch of Reionization (6 < z < 11)
• identify and study hundreds of rare quiescent galaxies at z > 4 and
• directly measure the evolution of the stellar mass to halo mass relation out to z ~ 2.5.

Nick Scoville, the Francis L. Moseley Professor of Astronomy at Caltech (Emeritus), was recently elected to the National Academy of Sciences in recognition of his distinguished and continuing achievements in original research! Nick is the PI of the original COSMOS HST/ACS observations. Congratulations!

The new COSMOS catalog is out and its accompanying paper is accepted!

The catalog contains 1 million sources measured in more than 30 photometric bands from the UV to the infrared. For the extraction of the photometry, our international team applied a new prior-based method to go even deeper and to obtain more robust measurements for blended sources. The catalog also contains photometric redshifts and other physical properties of the galaxies measured from their photometry using spectral energy distribution (SED) fitting codes like LePhare and Eazy.

This catalog is a major milestone for COSMOS, combining its multi-wavelength data consistently, and opening up new avenues to explore galaxy evolution.

You can download the catalog at https://cosmos2020.calet.org to use it for your own science!

A team of COSMOS researchers studied jets escaping active galactic nuclei (AGN) to investigate what causes their bending. For this, they used radio data from the VLA and X-ray observations from Chandra/XMM-Newton to measure the "bent angle", i.e., the angle the jets form to each other in a two-sided source. The angle is related to the environment in which the AGN hosts reside and compared to magnetohydrodynamic simulations. It is found that the evolution of the environment surrounding the sources affects their radio structures and allows for more space for jet interactions.

When the James Webb Space Telescope (JWST)—the long-awaited successor to the Hubble Space Telescope—becomes operational in 2022, one of its first orders of business will be mapping the earliest structures of the universe. A team of nearly 50 researchers led by scientists at Rochester Institute of Technology and University of Texas at Austin will attempt to do so through the COSMOS-Webb program, the largest General Observer program selected for JWST’s first year.

Over the course of 208.6 observing hours, the COSMOS-Webb program will conduct an ambitious survey of half a million galaxies with multi-band, high-resolution near infrared imaging and an unprecedented 32,000 galaxies in mid infrared. The scientists involved said that because COSMOS-Webb is a treasury program, they will rapidly release data to the public so it can lead to countless other studies by other researchers.