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Ricardo Chávez

Research Fellow

Hi!_

I am currently a CONACyT Research Fellow at UNAM’s Institute of Radioastronomy and Astrophysics (IRyA). My research interests are on theoretical and observational cosmology, starbursts, and galaxy formation and evolution. I am researching the origin and properties of stellar populations in galaxies near and far using photometric and spectroscopic analysis, and by modeling their spectral energy distribution using stellar population synthesis models. I am also studying the history of the evolution of the Universe using a variety of cosmological tracers.

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Resume_

I have the following research interests:

Star formation.
HII Regions.
Reionization.
Galaxy formation and evolution.
Dark Energy.
Comological parameters.

Current Position

Instituto de Radioastronomía y Astrofísica

CONACyT Research Fellow

2019 – Present

I am researching the origin and properties of stellar populations in galaxies near and far using photometric and spectroscopic analysis, and by modeling the spectral energy distribution using stellar population synthesis models. I am also studying the history of the evolution of the Universe using a variety of cosmological tracers.

Appointments held

Instituto de Radioastronomía y Astrofísica, UNAM, México

2018 - 2019

Postdoctoral Fellow

Cavendish Lab. & Kavli Institute for Cosmology, University of Cambridge, UK

2016 - 2018

Postdoctoral Fellow

LMT, México

2014 - 2016

Support Astronomer

Education

Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE)

2010 - 2014

PhD in Astrophysics
Constraining the Parameter Space of the Dark Energy Equation of State Using Alternative Cosmic Tracers

Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE)

2008 - 2010

MSc in Astrophysics

ITCC

2003 - 2008

BEng in Mechatronics

General skills

Paython 95%

IDL 80%

IRAF 60%

SQL 80%

C 65%

FORTRAN 55%

MCMC sampling 90%

Bayesian inference 85%

Recent papers_

Cosmological constraints using the newest VLT-KMOS H II galaxies and the full Planck CMB spectrum

Cosmological constraints using the newest VLT-KMOS H II galaxies and the full Planck CMB spectrum

We present novel cosmological constraints based on a joint analysis of our H II galaxies (HIIG) Hubble relation with the full Planck cosmic microwave background (CMB) anisotropy spectrum and the baryon acoustic oscillations (BAO) probes. Our independent constraints compare well with those based on the 'Pantheon' compilation of SNeIa data, which we also analyse. We find our results to be in agreement with the conformal Λ cold dark matter (ΛCDM) model within 1σ.

Key Words:

  • galaxies: high-redshift
  • cosmological parameters
  • dark energy
Paper in ADS
Early science with the Large Millimeter Telescope: a 1.1 mm AzTEC survey of red-Herschel dusty star-forming galaxies

Early science with the Large Millimeter Telescope: a 1.1 mm AzTEC survey of red-Herschel dusty star-forming galaxies

We present LMT/AzTEC 1.1 mm observations of ∼ 100 luminous high-redshift dusty star-forming galaxy candidates from the Herschel-ATLAS survey. With an effective 𝜃FWHM ≈ 9.5 arcsec angular resolution, our observations reveal that at least 9 per cent of the targets break into multiple systems with SNR ≥ 4 members (i.e. without considering close mergers). The fraction of multiple systems increases to ∼ 23 per cent (or more) if some non-detected targets are multiples, as suggested by the data.

Key Words:

  • submillimetre: galaxies
  • galaxies: starburst
  • galaxies: high-redshift
Paper in ADS
Independent cosmological constraints from high-z HII galaxies: new results from VLT-KMOS data

Independent cosmological constraints from high-z HII galaxies: new results from VLT-KMOS data

We present independent determinations of cosmological parameters using the distance estimator based on the established correlation between the Balmer line luminosity, L(Hβ), and the velocity dispersion (σ) for HII galaxies (HIIG). These results are based on new VLT-KMOS high spectral resolution observations of 41 high-z (1.3 ≤ z ≤2.6) HIIG combined with published data.

Key Words:

  • cosmology: dark energy
  • galaxies: starburst
  • cosmological parameters
Paper in ADS
Internal kinematics of giant H II regions in M101 with the Keck Cosmic Web Imager

Internal kinematics of giant H II regions in M101 with the Keck Cosmic Web Imager

We study the kinematics of the GEHR NGC 5455 and NGC 5471 located in the galaxy M101, using integral field observations that include the Hβ and [O III] λ 5007 emission lines, obtained with the Keck Cosmic Web Imager (KCWI).

Key Words:

  • H ii regions
  • galaxies: ISM
  • ISM: kinematics and dynamics
Paper in ADS
Chemodynamics of green pea galaxies - I. Outflows and turbulence driving the escape of ionizing photons and chemical enrichment

Chemodynamics of green pea galaxies - I. Outflows and turbulence driving the escape of ionizing photons and chemical enrichment

We investigate the ionised gas kinematics, physical properties, and chemical abundances of SDSS J142947.00+064334.9, an HIIG at z ∼ 0.17, with strong, double-peak Lyα emission and indirect evidence of Lyman continuum (LyC) leakage.

Key Words:

  • galaxies: abundances
  • galaxies: kinematics and dynamics
  • (cosmology:) reionization
Paper in ADS
Independent cosmological constraints from high-z H II galaxies

Independent cosmological constraints from high-z H II galaxies

We present new high spectral resolution observations of 15 high-z (1.3 ≤ z ≤2.5) H II galaxies (H II G) obtained with MOSFIRE at the Keck Observatory. These data, combined with already published data for another 31 high-z and 107 z ≤0.15 H II G, are used to obtain new independent cosmological constraints.

Key Words:

  • galaxies: starburst
  • cosmological parameters
  • cosmology observations
Paper in ADS
From Giant H II regions and H II galaxies to globular clusters and compact dwarf ellipticals

From Giant H II regions and H II galaxies to globular clusters and compact dwarf ellipticals

We model the photometric and dynamical evolution over a Hubble time of the massive gravitationally bound systems that populate the tight relation between absolute blue magnitude and velocity dispersion (MB - σ) of GHIIR and HIIG and compare the resulting relation with that one of old stellar systems: globular clusters, elliptical galaxies, and bulges of spirals.

Key Words:

  • ISM: evolution
  • globular clusters: general
  • galaxies: star clusters: general
Paper in ADS
An independent determination of the local Hubble constant

An independent determination of the local Hubble constant

We present new data for 36 giant H II regions in 13 galaxies of the anchor sample that includes the megamaser galaxy NGC 4258 from wich we estimate the value of Hubble parameter as 71.0 ± 2.8(random) ± 2.1(systematic) km s- 1Mpc- 1.

Key Words:

  • H II regions
  • galaxies: star formation
  • distance scale
Paper in ADS

Teaching_

Cosmology

Cosmology

This is a course on Cosmology aimed at second semester master students (IRyA, UNAM). It covers an introduction to General Relativity and FRW cosmological models, the phyiscs of the early Universe, inflation, primordial nucleosynthesis, CMB and formation of large scale structure. I taught this course during 2020 autumn semester.

Resources:

Video lectures on YouTube
Stellar Astrophysics

Stellar Astrophysics

This is a course on Stellar Astrophysics aimed at first semester master students (IRyA, UNAM). It covers an introduction to radiation physics such as radiative transfer and local thermodynamic equilibrium, also it introduces the physics of stellar atmospheres with concepts such as opacity, line formation and stellar winds. I am currently teaching this course.

Resources:

Video lectures on YouTube

Get in touch_

Or just write me a letter here_