Research projects

Publications

Talks

Teaching

Short Biography

PhD thesis

Outreach

AGNfitter

Research projects

In this word-cloud you can see the most frequenty used keywords in my first-author publications. My current research focusses in understanding the most luminous phases of galaxy evolution in the early Universe. Here you can find some selected results:

The Spectral Energy Distributions (SEDs) of AGN and star-forming galaxies

A multiwavelength approach is crucial to achieve a complete and unbiased physical characterization of galaxies and AGN.
In CR+16 we presented AGNfitter, a probabilistic tool to fit SEDs of galaxies and AGN from a Bayesian approach, thus ensuring a robust handling of uncertainties in the parameters.

AGNfitter is publicily available and can be downloaded from here.





The low-frequency radio as a SFR tracer

The radio regime is a reliable dust-unbiased tracer of star-formation rate (SFR) due to its tight correlation with the IR (infrared-radio correlation, IRC). While radio observations at frequencies higher than 1.4 GHz have been extensively used for SFR studies, this is not the case for the low frequencies. Low-frequency observations, however, are very promising since they can go deeper than high-frequencies due to the negative power-law shape of the radio SED.

In CR+17, we calibrate the low-frequency radio (150 MHz) as an SFR tracer for the first time. The LOFAR Bootes field, as one of the deepest radio galaxies surveys to-date, allowed us to characterize the IRC to high-redshifts (0<z<2.5). We found that the infrared-radio correlation is not constant as a function of redshift, but decreases following the formula on the right.

The shape of the radio continuum of galaxies and AGN

In CR+17 we presented the first high-redshift galaxy and AGN study of a LOFAR survey (Bootes), one of the deepest surveys to-date. We constructed for the first time the low-to-high frequency radio SED for a statistical sample of high-z star-forming galaxies and AGN (0<z<2.5), using four different radio interferometers: LOFAR, VLA, WSRT and GMRT.

We found a significant difference in the shape of the radio continuum between AGN and star-forming galaxies. This result suggests two possible scenarios: a) instrinsic physical differences in the production of radio emission of these both populations or b) significat absorption at low frequencies in star-forming regions.
Multi-wavelength + high-resolution:

Off-set distributions of stars, gas and dust

In CR+18, we combined ALMA and HST observations of four submillimeter galaxies to study the distributions of the molecular gas emission (CO line, lower-left panel and white countours in the righ panel) and the optical/NIR stellar emission (background image in right panel).

We find that in most cases these components are significantly off-set, suggesting these are originated in different physical regions!
Most strikingly, we also find singificant off-sets when comparing the stellar to the dust continuum emission. This, together with similar finding of other high-res observations, has implications against energy balance assumptions in integrated SED fitting.

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Extended molecular gas and compact dust:

Using larger samples of submillimeter galaxies (SMGs) we apply a statistical approach through stacking to study the differences in the extents of gas and dust, as shown by their radial profile.

We find that the average extent of the CO emission in SMGs is more than twice as large as the dust continuum emission.

We investigate the origin of this difference by modelling both the gas and dust emission consistently through radiative transfer. We found that this apparent size difference can be explained by temperature and optical depth gradients alone, and does not necessarily imply different physical sizes


First & Second author publications


AGNfitter: A Bayesian MCMC Approach to Fitting Spectral Energy Distributions of AGNs
Calistro Rivera et al. (2016) - ApJ,833,98C img
The LOFAR window on star-forming galaxies and AGNs - curved radio SEDs and IR-radio correlation at 0<z<2.5
Calistro Rivera et al. (2017) - MNRAS.469.3468C img
LOFAR-Boötes: properties of high- and low-excitation radio galaxies at 0.5 < z< 2.0
Williams, Calistro Rivera et al. (2018) - MNRAS, 475, 3429W img
Resolving the ISM at the Peak of Cosmic Star Formation with ALMA: The Distribution of CO and Dust Continuum in z ~ 2.5 Submillimeter Galaxies
Calistro Rivera et al. (2018) - ApJ,863,56C img
The Distribution of [CII], CO and Dust Continuum in z ~ 3 Submillimeter Galaxies
Rybak, Calistro Rivera et al. (2019) - ApJ,876,12R img
The multiwavelength properties of red QSOs - Evidence for dusty winds as the origin of QSO reddening
Calistro Rivera et al. (2021) - A&A, 649A, 102C img
The CosmoAmautas project for equitable scientific education in Peru
Calistro Rivera et al. (2022) - Nature Astronomy, 6, 170 img
The Quasar Feedback Survey: Characterising CO excitation in quasar host galaxies
Molyneux, Calistro Rivera et al. (2023) - MNRAS (PhD student project) img
Ubiquitous radio emission in quasars: predominant AGN origin and a connection to jets, dust and winds
Calistro Rivera et al. (2024) - A&A img

Other publications: 50 refereed publications as co-author. img


Teaching - Research Group



Research group:
Excellent students from different parts of the world with whom I have the pleasure to work
on different research projects on galaxy and AGN Evolution.

Upper row: Bruno Rodriguez (Internship student at ESO/ PUCP, Perú),
Laura Martinez (Internship student at ESO/ PhD student at PUC Chile/ UIS Colombia).
Lower row: Stephen Molyneux (PhD student at ESO/ Liverpool UK),
Katy Proctor (PhD student at UWA, Australia).
Tiny image on the lower-right corner: Yours truly


Supervision of students:

  • 2020 - present : Primary Advisor of the PhD project of Stephen Molyneux (ESO/ Liverpool)
    Topic: The impact of QSO feedback on the molecular ISM (co-supervised with Carlos de Breuk (ESO), Renske Smit (LJMU))

  • 2020 - present : Primary Advisor of the ESO internship project of Bruno Rodriguez (ESO/ PUCP, Perú)
    Topic: Tracing the imprint of AGN in statistical samples of quiescent galaxies.

  • 2020 - present : Primary Advisor of the ESO internship of Laura Martinez Ramirez (ESO/ UIS, Colombia/ PUC, Chile)
    Topic: Modelling the SEDs of AGN from the radio to the X-rays.

  • 2021 : Primary Advisor of the ESO internship of Katy Proctor (UWA, Australia)
    Topic: The ISM the first quasar (co-supervised by Roland Szakacs and Gergo Popping)

  • 2018 : Primary Advisor of the Bachelor Thesis of Danker Roozemond (Leiden STRW).
    Topic: The AGN contribution to sub-millimeter galaxies.

  • 2017 : Primary Advisor of the Bachelor Thesis of Auke Bruinsman (Leiden STRW)
    Topic: radio jets of a nearby AGN.




Astronomy Education - Teacher Training

  • 2021: Astronomy Book - CosmoAmautas
    Editor of Astronomy Education Book for the IAU/OAD CosmoAmautas project. (in Spanish, link to the Arxiv)

  • 2021, 2022: Online Teaching material and delivery
    Development and delivery of Astronomy Education Workshop for 120 school teachers in Peru, as PI of the IAU/OAD CosmoAmautas project.



University courses - Teaching assistant

  • 2016 - 2017: Galaxies: Structure and Dynamics
    Teaching Assistant of Rychard Bouwens' lecture on Galaxies at Leiden Observatory in the Fall 2016.

  • 2013 - 2014: Physics Laboratory
    Tutor of the Physics laboratory for Bachelor students at Heidelberg University. Topic: Electrodynamics.


Short Bio


Professional Experiencie

  • 2019 - present:
    ESO Postdoctoral Fellow (ESO Garching, Germany)
  • 2014 - 2019:
     Ph.D. researcher in Astronomy (Leiden Observatory, the Netherlands)
    • 2014:
       Short-term Research Project (MPIA, Germany)


Education

  • 2014 - 2019:
    Ph.D. in Astronomy (Leiden Observatory, the Netherlands)
    Thesis : The Colours of the Extreme Universe
    Supervisor: Dr. Jacqueline Hodge, Prof. Huub Röttgering

  • 2012 - 2014:
    M.Sc. in Physics (Heidelberg University / MPIA, Germany)
    Thesis: Classification of Obscured AGN through SED-fitting
    Supervisor: Dr. Joseph Hennawi, Dr. Elisabeta Lusso

  • 2008 - 2011:   
    B.Sc. in Physics (Heidelberg University / Institute for Theoretical Astrophysics,Germany)
    Thesis: The Lensed Temperature Anisotropy of the CMB
    Supervisor: Prof. Matthias Bartelmann


Awards & Grants



Media

I grew up in Lima, the capital of Perú. Although Perú is predominantly known as an andean country, Lima is a coast city and the multifaceted home of around ten million people. Lately Lima has become very popular in the international comunity as a culinary paradise. Friendly advice: look for the closest Peruvian restaurant to your home, it's delicious!

Here, my school education took place mainly in the Peruvian-German School Alexander von Humboldt.
My undergraduate alma-mater is the University of Heidelberg, located in a beautiful city in the south of Germany of the same name.

Here, I completed the Bachelor and Master Studies in Physics, as a DAAD scholarship holder.

My research career started at the Max Plack Institute for Astronomy (MPIA), where I worked on AGN and SED-fitting. Since this period I have worked in collaboration with Joseph Hennawi (UCSB), Elisabeta Lusso (Durham Universtiy) and David Hogg (Flatiron Institute/NYU/MPIA).
I did my PhD Research at Leiden Observatory, in the Netherlands. Here I was part of the sub-mm astronomy group, led by Jacqueline Hodge, and the radio astronomy group, lead by Huub Rottgering. During my PhD I worked as well in close collaboration with Prof. Ian Smail (Durham University) and Prof. Martin Hardcastle (University of Hertfordshire).


I am currently appointed as an ESO postdoctoral Fellow at the ESO Headquarters in Garching bei München, Germany. The campus is a few kms from the Bavarian city of Munich, very close to beautiful mountains which you can even see from the ESO offices. Here I conduct independent research on galaxy and AGN evolution and design and supervise student research projects (see research group). As part of my functional duties, I am a representative of the ESO Science Ambassadors programme and coordinate astronomy outreach events around the world led by ESO scientists, and am also part of the ALMA Regional Centre (ARC).


Astronomy for Development/ Science Communication

I believe astronomy has an inmense potential to inspire, connect and improve society beyond its research achievements.
I am therefore passionate about promoting other aspects of astronomy, such as scientific education, communication and
the use of astronomy as a tool for sustainable social development.

In particular, I am the PI of the program CosmoAmautas (Amautas = teacher/ knowledgeable person in the Quechua language) , a program of astronomy for development in Peru funded by the IAU/OAD and sustained by the volunteer work of a team of 15 astrophysicists, physics students, educators, and designers .

CosmoAmautas aims to contribute to the development of an astronomical community in Peru (through university level research) and at the same time uses astronomy as a tool to improve and innovate scientific education in schools, in particular in rural areas of the country, through teacher trainings and extra-curricular astronomy clubs.

Due to the pandemic, the CosmoAmautas Teacher Training Workshop has been held online, sharing hands-on activities and lectures on different topics of astronomy with 50 high-school teachers from different regions, who have been selected based on their motivation and interest. You can find a closer description of our activities and the impact of the program in this article in Nature Astronomy , and in our webpage and social media.



Other Science Communication Activities

  • ESO Science Ambassador Representative (2020 - )
    As part of my duties at ESO I coordinate outreach and education activities of ESO scientists
    together with ESO Fellow George Lansbury, supporting them with material, contacts and training
    to promote astronomy and ESO science at schools and Science Festivals
    in ESO member states.

  • Club de Ciencias, Colombia (2019)
    As part of the program Club de Ciencias (Colombia), I organised and led a one-week astronomy club
    on galaxies for high-school students in Bucaramanga, Colombia, in collaboration with local
    astronomers Juan Carlos Basto Pineda and Jhonattan Pisco.
    Below you can find some pictures and a video with the activities we carried on in the astronomy club
    (courtesy of Juan Carlos Basto).

  • Discovery Club, Universe Awareness (2018):
    Organized astronomy activities to groups of children that live in refugee centers in the Netherlands,
    with the aim to use astronomy to inspire, educate and entertain them.

  • Mohlo Ababa (2019)
    Contributed with the development of the curriculum for the Mohlo Ababa project in South Africa.

  • Teacher Training in Ethiopia (2019)
    Contributed to the school-teachers training and outreach activities organized under the IAU Symposium 356 in Ethiopia


    • Selected presentations I gave at conferences and seminars

    Year
    Name
    Talk
    City
    Link
    2014
    Southern Cross Conference 2014 ’Powerful AGN’
    contributed
    Port Douglas, Australia
    2015
    Galaxy studies in the mid-infrared - Symposium EWASS15
    contributed
    Tenerife,Spain
    2015
    The infrared-radio correlation - Special Session EWASS15
    contributed
    Tenerife,Spain
    2016
    Cosmic Dawn of Galaxy Formation: Linking observations and theory
    contributed
    Paris, France
    video gif
    2016
    AGN: What’s in a name? - ESO workshop <
    contributed
    Garching - Germany
    2016
    Latinamerican Regional IAU Meeting LARIM
    contributed
    Cartagena - Colombia
    2017
    Distant Galaxies from the Far South
    contributed
    Bariloche, Argentina
    2018
    The ISM as a window onto galaxy evolution - Symposium EWASS18
    contributed
    Durham, UK
    2018
    CANDELS: The art of measuring physical parameters in galaxies
    invited
    Riverside, US
    2018
    Lorentz Center workshop on Photometric Redshifts)
    invited
    Leiden, The Netherlands
    2018
    IAU Symposium 341: Challenges in Panchromatic Galaxy Modelling
    contributed
    Osaka, Japan
    2020
    EAS 2020 - The multiwavelength properties of red QSOs: a low-frequency radio (LOFAR) perspective
    contributed
    Online
    2020
    EAS 2020 - COSMOamautas: Astronomy Education as a tool for Development in Peru
    invited
    Online
    2020
    EAS 2020 - Resolving the ISM at the peak of cosmic star formation with ALMA -- Sub-arcsec CO, dust, and Halpha maps of z~2-3 SMGs
    contributed
    Online
    2021
    Seminar UCL
    invited
    London, UK


    PhD Thesis

    I defended my PhD thesis The Colours of the Extreme Universe on January 10, 2019.
    Here you can find an electronic version of my thesis book.
    Thesis Gabriela Calistro Rivera