Seminario de Astrofísica en el IFIS. Este martes 13 de octubre a las 14:30 hrs, la Dr. Kseniia Telikova, investigador postdoctoral del Instituto de Astrofísica de la Pontificia Universidad Católica de Chile, presentará en el Instituto de Física el seminario:

“Gas in and around galaxies at early cosmic times: a multi-wavelength view”.

La presentación se realizará en la Sala 208 del Instituto de Física (IFIS), 2° piso, Edificio de Ciencias, Campus Curauma, PUCV.

Revisa el abstract de la presentación:

Early galaxies are shaped by complex feedback and accretion processes occurring across a wide range of spatial and timescales. Recent advances with JWST and ALMA have changed our understanding of high-redshift galaxies and led to some of the most intriguing discoveries of the past decade. One such discovery is the presence of extended [CII] halos around high-redshift galaxies, reaching up to 10 kpc and about 2-3 times more extended than the stellar light. While these [CII] halos are found to be common at z>4, their formation mechanisms are still not well understood.

Using ALMA and JWST observations of gas and dust in a sample of star-forming galaxies at z~4−6, we explore the role of radiative shocks in shaping gas properties of these galaxies and, in particular, their potential contribution to driving [CII] halos. By combining rest-frame optical emission line ratios with gas velocity dispersion measurements, we derive a conservative lower limit of 1% for the incidence rate of shocks in main-sequence galaxies at z=4-6. We also find that half of our galaxies show outflows, which are likely driven by AGN activity or star formation rather than by mergers or large-scale tidal interactions.

Finally, I will present results from a student project on Ly-alpha emitters as probes of the intergalactic medium using MUSE, and I will briefly discuss some of our upcoming observational programs.

Seminario de Astrofísica en el IFIS. El próximo martes 25 de agosto a las 14:30 hrs, la Dra. Odette Toloza (UTFSM), presentará en el Instituto de Física el seminario:

“Feeding, Erupting, and Bursting: The restless lives of accreting white dwarfs”.

La presentación se realizará en la Sala 208 del Instituto de Física (IFIS), 2° piso, Edificio de Ciencias, Campus Curauma, PUCV.

 

Seminario de Astrofísica en el IFIS. El próximo martes 16 de junio a las 14:30 hrs, Constanza Castillo, estudiante de magíster en astrofísica (UC), presentará en el Instituto de Física el seminario:

“Formation of O-bearing Complex Organic Molecules in protoplanetary disks”.

La presentación se realizará en la Sala 208 del Instituto de Física (IFIS), 2° piso, Edificio de Ciencias, Campus Curauma, PUCV.

Revisa el abstract de la presentación:

Protoplanetary disks around young stars are the environment where planets form, making it crucial to characterize their composition and spatial distribution, as part of this material can be incorporated into forming planets. In this context, Complex Organic Molecules (COMs) are particularly interesting, as they are considered a bridge to prebiotic molecules and the initial steps of life’s formation. Among them, methanol (CH3OH), the simplest COM, is a key precursor to more complex species. However, its detection in disks remains challenging, as it is primarily locked in icy grains. Formaldehyde (H2CO), a brighter and more commonly detected molecule that shares formation pathways with methanol, can thus serve as a tracer of organic chemistry in disks. This work retrieves the excitation conditions and column densities of H2CO through disk-averaged and radially resolved analyses. By extending these studies beyond the small number of well-characterized disks currently available, we aim to compare the chemical properties of different planet-forming environments and constrain the origin of oxygen-bearing organic molecules in protoplanetary disks.

Seminario de Astrofísica en el IFIS. Este martes 09 de junio a las 14:30 hrs, el Dr. Sunil Simha, investigador postdoctoral (Northwestern University and The University of Chicago), presentará en el Instituto de Física el seminario:

“FRBs as foreground probes: Recent results from the CHIME collaboration and ongoing work with FLIMFLAM”.

La presentación se realizará en la Sala 208 del Instituto de Física (IFIS), 2° piso, Edificio de Ciencias, Campus Curauma, PUCV.

Revisa el abstract de la presentación:

The field of Fast Radio Bursts (FRBs) is experiencing a rapid growth in FRB detections spearheaded by the CHIME/FRB collaboration. The CHIME Outrigger telescopes have come into full operation since early 2025 and have enabled sub-arcsecond-scale VLBI localizations of tens of published FRBs to date. Subsequently, our optical follow-up led by the F^4 team is steadily associating the bursts with their hosts and obtaining spectroscopic redshifts for these bursts. Armed with the FRB dispersion measures (DM) and their host redshifts, we are now able to constrain the gas distribution along the FRB sightlines. In my talk, I will provide an overview of our early results, including: (1) constraints on galactic feedback models prevalent in FRB hosts, (2) baryon retention fractions in group and cluster halos, (3) host galaxy ISM constraints from an extremely bright nearby (~40 Mpc) burst, and (4) a statistical hint of halo gas around M31. I will also highlight some of the ongoing work on the FLIMFLAM project, an effort to constrain gas in halos and the IGM via spectroscopic maps of foreground galaxies.

Seminario de Astrofísica en el IFIS. El próximo martes 26 de mayo a las 14:30 hrs, el Dr. Eduardo Ibar, académico de la Universidad de Valparaíso, presentará en el Instituto de Física el seminario:

“The JWST Emission Line Survey (JELS)”.

La presentación se realizará en la Sala 208 del Instituto de Física (IFIS), 2° piso, Edificio de Ciencias, Campus Curauma, PUCV.

Revisa el abstract de la presentación:

The H-alpha (Ha) emission is the best-calibrated star-formation rate (SFR) tracer. Previous to JWST, surveys mapped the evolution of Ha emitters out to the peak of the Cosmic SFR Density (CSFRD) at z~2.5. Beyond this redshift, samples of star-forming galaxies and estimates of the CSFRD were almost ubiquitously based on rest-frame UV observations with HST. In this talk, we describe new JWST NIRCam’s narrow-band filters to observe a 65 arcmin^2 in COSMOS to identify several 100s of line-emitting galaxies. We consider difference imaging between closely-spaced narrow and broad band filters, to find line-emitting galaxies to provide the first clean and robust sample of homogeneously selected star-forming galaxies into the Epoch of Reionization (at z~6.2 and 8.2). We measure the ionised gas structures of these galaxies at sub-kpc resolution, determine how the relationship between UV and ionised gas varies with host galaxy properties, and tackle the physical processes driving the star formation activity at different reshifts. We describe also the properties of a newly discovered population of Paschen emitters at Cosmic Noon (Pa-alpha@z~1.5, Pa-beta@z~2.6) including their SED properties, their contribution to the CSFRD, and upcoming future follow-up campaigns.