The "Centro de Estudios de Física del Cosmos de Aragón" (CEFCA) invites applications for one predoctoral positions in Astrophysics. This action is funded by the Spanish Ministry of Science, Innovation and Universities (MCIU/AEI/10.13039/501100011033 / FEDER, UE) with grant PREP2023-001336 associated to the project LA NATURALEZA Y EVOLUCION COSMICA DE LAS GALAXIAS CON LINEA DE EMISION EXTREMA "XTREM" (PID2023-147386NB-I00).

CEFCA is a research institution located in Teruel, Spain, in charge of the operation, data management and scientific exploitation of the Observatorio Astrofísico de Javalambre (OAJ), an astronomical facility specifically suited for carrying out large astronomical surveys with very large field-of-view (FoV) telescopes: the 2.5m Javalambre Survey Telescope (JST250; 3deg diameter FoV) and the 83cm Javalambre Auxiliary Survey Telescope (JAST80; 2deg diameter FoV).

JST250 is equipped with JPCam, a 1.2Gpix panoramic camera consisting of a mosaic of 14 CCDs of ~9.2k x 9.2k pix. The JPCam/JST250 system provides a 4.1 deg2 FoV and hosts a complete new set of 54 filters of 145A width, covering the whole optical spectral range. During the next years, JPCam/JST250 will be mostly devoted to carry out the Javalambre Physics of the accelerating Universe Astrophysical Survey (J-PAS), , which is producing photo-spectra of hundreds of millions of astronomical objects with a wide range of applications in Astrophysics and Cosmology. The J-PAS early data release, covering 12 deg2, was made public in November 2024. JAST80 is equipped with the panoramic camera T80Cam, hosting one CCD identical to those in JPCam. The T80Cam/JAST80 system provides an effective FoV of 2 deg2. Since 2016, it is primarily devoted to conduct the Javalambre Photometric Local Universe Survey (J-PLUS), whose third data release, amounting ~3200deg2 was public in December 2022.

The OAJ data is reduced, calibrated and released by the Unit for Data Processing and Archiving (UPAD) at CEFCA. In addition, the data from the main CEFCA surveys is validated and exploited at scientific level by the Research Area at CEFCA.

The PhD project will be pivotal in the XTREM long-term research program. Its main objectives are the scientific exploitation of the James Webb Space Telescope (JWST) and the wide-field spectrophotometric mapping of J-PAS to study the most extreme emission-line galaxies (EELGs) through cosmic time. XTREM will primarily study low-mass galaxies, compact in size, exhibiting high star formation rates, and easily identifiable in the extragalactic ecosystem due to their extreme emission lines and faint continuum emission, even in broad- and medium-band photometry. Recent work on high-redshift galaxies highlights the key role of EELGs as significant drivers of cosmic Hydrogen reionization and early chemical evolution at z > 6 while providing a brief but crucial glimpse into the evolution of galaxies during major phases of galaxy growth at later cosmic epochs. While EELGs are thus excellent laboratories for studying starburst-driven evolution of galaxies in quasi-pristine environments that are common in the early universe, they appear increasingly rarer at lower redshifts. Detailed studies and comparison of their main properties across cosmic time are now feasible with HST, JWST, Euclid, and big ground-based telescopes. However, a statistically complete census and characterization of the physical properties of EELGs are yet much needed. This is key for a better understanding of their significance on the cosmic star formation history and for selecting representative samples enabling detailed studies, for example on the physics of their interstellar medium and the role of starbursts and feedback in shaping the chemical enrichment and the production and escape of ionizing photons in such galaxies. With this in mind, XTREM aims at comprehensively and statistically studying the population of EELGs from redshift z = 0 to the reionization epoch (z > 6).

To achieve this, we plan to 1) build the most comprehensive samples available with optical spectro-photometry from the ground for nearby objects using JPAS and DESI, leveraging their extensive coverage and precise redshifts, and 2) select and study high-z EELGs from deep cosmological fields using photometric color criteria and spectroscopic observations with JWST/NIRSPec and NIRCam, and ground-based follow-ups (e.g. GTC, VLT, ALMA).

In this context, CEFCA is seeking one predoctoral researcher to conduct ambitious research centered on the following goals: a) the star formation history of EELGs; b) the internal (stellar formation, dynamics) and external processes that influence the initiation and propagation of star formation; c) the chemical abundances defining this population at all redshifts via main fundamental relations (e.g. mass-metallicity-SFR) and their interpretation in terms of chemical evolution models; d) the gas kinematics of these galaxies, whether they rotate like disks or are dominated by turbulence and outflows, and lastly e) the ISM physics to understand the escape of ionizing photons and how these processes might be applicable to reionization galaxies.

The predoc researcher will work under the supervision of Dr. Ricardo Amorín, PI of the project, and will engage in all the activities planned for XTREM, including frequent working visits to XTREM collaborators at IAA-CSIC, and training visits in international partners, e.g. INAF-Rome and STScI. The contract will be conducted at the CEFCA’s headquarters in Teruel. In addition to the salary and the needed equipment, funds to assist national and international meetings and workshops will be provided.

Additional information, including details about the neded documentation and the evaluation process can be found here:

https://www.cefca.es/cefca_en/reference_0127