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Formation and Evolution of Galaxies

 

Galaxies have progressively formed through a complex combination of gas accretion, star formation, and merging with other galactic units. The Formation and Evolution of Galaxies research line aims:

1) to survey the 3D structure of the Milky Way and resolve stellar populations in its Globular Cluster system, its satellite galaxies, and in other nearby Galaxies as a way to confirm models of galaxy formation in various cosmological scenarios.

2) To disentangle among the different scenarios proposed to explain the star formation history of the Universe and decipher the role of merging, accretion and supermassive black holes in the centers of galaxies; the IAC will collect an unprecedentedly large sample of superb-quality spectra of distant galaxies with GTC and VLT and obtain ultra high spatial resolution imaging and 3D spectra of the nearest galaxies with GTCAO+FRIDA to explore the supermassive black hole activity cycle and its influence on galaxy evolution.

3) To study the physics of star formation and the conditions of the interstellar medium in the first galaxies conducting follow-up studies with GTC and the Millimeter Interferometers ALMA, and IRAM of high-z galaxies discovered in the extragalactic surveys with the Herschel Submillimeter Space Observatory (co-Is are I. Pérez- Fournón and J. Cepa) and the Spitzer satellite; and narrow-band surveys and spectroscopic follow-up of Lyman alpha emitters with the unique capabilities of the OSIRIS (P.I. J. Cepa) and EMIR (P.I. F. Garzón) optical and infrared spectrographs on GTC. Use the nearby galaxies, particularly those at low Z, as probes for the early Universe.

4) The IAC leads a collaboration to obtain spectroscopy of all the known gravitational lenses using the VLT, Magellan, MMT, GTC and in the future HARMONI (the first light instrument of the E-ELT, co-I E. Mediavilla) and detect the presence of dark matter in the halos of galaxies (MACHOS and subhalos) by measuring the difference in magnification of the continuum and the emission lines.

5) The recently created theoretical/simulation group led by the advanced Severo Ochoa fellow Claudio Dalla Vecchia aims at linking observations and theory; the group, together with the international collaborations of its members, will be performing simulations of galaxy formation and evolution in order to strengthen the interpretation of observational data and provide predictions for future observations.

 

Goals:

  • Measure the 3D structure of the Milky Way and resolve stellar populations in its Globular Cluster system, its satellite galaxies and in nearby galaxies to constrain models of galaxy formation in cosmological scenarios.
  • Study the physics of star formation and the conditions of the interstellar medium over the history of the Universe and decipher the role of merging, accretion and supermassive black holes in the centers of galaxies.

 

Specific Scientific Outputs:

2016

  • An international scientific team in which the IAC participates has discovered that the largest galaxies in the universe are developing in cosmic clouds of cold gas. The finding, published in the journal Science, has been possible using radio telescopes in Australia and the US. 
  • Observations made with the Atacama Large Millimeter Array (ALMA) of the central region of NGC 1068, a prototypical Seyfert type 2 galaxy, have allowed to resolve for the first time the torus of dust and gas in the center of this active galaxy. The study, which has IAC participation, has been published in The Astrophysical Journal Letters.
  • A team of IAC researchers have obtained the deepest image of a galaxy from the ground with the GTC. The image is ten times deeper than any other made with ground-based telescopes and allows us to observe the faint stellar halo of one of our neighboring galaxies, which supports the presently accepted model of galaxy formation (published in The Astrophysical Journal).
  • A statistical correlation has been found between the size of the spiral galaxies' bulb and the number of "tidal dwarf" satellite galaxies (remnants of the interaction between host galaxies), which reinforces the models without dark matter (study published in The Astrophysical Journal).
  • IAC scientists have participated in the study of a "tadpole" galaxy observed with the Hubble Space Telescope, whose results reveal how cosmic gas triggers the birth of stars in galaxies. This process, which is very difficult to observe, would thus explain the formation of galaxies like the Milky Way (published in The Astrophysical Journal).
  • A new Einstein ring has been discovered by an IAC PhD student during the analysis of images of the Sculptor dwarf galaxy. Its physical properties has been later analyzed with the OSIRIS spectrograph in the GTC (study published in MNRAS Letters).  
  • Two new methods have been developed based on the properties of the RR Lyrae variable stars to used them as probes of the first star formation events in galaxies and to study the early formation history of the Milky Way stellar halos (Martínez-Vázquez et al., 2016; Fiorentino et al. 2017).
  • An IAC team has obtained the first measurements of dynamic mass for an Ultra Diffuse Galaxy in the Virgo galaxy cluster (Beasley et al., 2016).
  • New stellar population models based on empirical stellar libraries have been published covering the wavelength range from 0.16 to 50 microns (Vazdekis et al., 2016). 

 

2017

  • IAC researchers have participated in a study that has observed, for the first time, the interstellar dust of one of the most distant galaxies known, thanks to observations made with ALMA (published in The Astrophysical Journal Letters).
  • A study led by the IAC has used the microlensing effect on quasars to estimate the number of intermediate mass primordial black holes in galaxies. The results suggest that the gravitational waves detected by the LIGO experiment came from black holes generated in the collapse of stars and not in the origin of the Universe (published in The Astrophysical Journal Letters).
  • A scientific team led by the IAC has detected and measured a set of super bubbles expanding in the interstellar medium of the interacting galaxies "Antennae". The team has used the GHaFaS instrument, which can obtain a velocity map of an entire galaxy using the emission of ionized hydrogen, in the WHT and a method of analysis developed by themselves (study published in MNRAS).
  • A scientific team led by the IAC has found a precise way to measure the rate of star formation in galaxies using the range of radio frequencies between 1 and 10 GHz (published in The Astrophysical Journal).
  • An international team led by IAC researchers has discovered one of the brightest distant non-active galaxies so far known. The discovery of BG1429+1202, 11.4 billion light-years away, has been possible thanks to the effect of gravitational lens produced by a massive elliptical galaxy in the line of sight to the object. The results, published in The Astrophysical Journal Letters, are part of the BELLS GALLERY project, based on the analysis of 1.5 million spectra of SDSS galaxies.
  • Deep spectroscopic observations of the galaxy group Abell 2151, made with AF2/WYFFOS at the WHT, allowed the identification of 360 galaxy members of the cluster. The study suggests that reddening of bright galaxies is independent of the environment, unlike for the population of dwarf galaxies (published in MNRAS).
  • An algorithm developed by the IAC researcher Sebastian Hidalgo to analyze data on star formation in the Universe has been selected to run in the global computing event "Global Azure Bootcamp 2017".
  • Images obtained with the infrared camera CIRCE installed in the GTC allow us to reveal the morphology of the host galaxy of a powerful active galactic nucleus. The study shows for the first time that the host galaxy of one of these active "Narrow Line Seyfert 1" galactic nuclei is an elliptical galaxy (study published in MNRAS Letters).
  • The HST "ISLAndS" project, which has obtained 111 orbits with the Hubble Space Telescope to study a representative sample of six spherical galaxies of M31, has made it possible to obtain the star formation history of these galaxies with a temporal resolution of ~ 1 Gigayear at old ages (Monelli et al. 2016; Skillman et al. 2017).

 

Previous results (2012 - 2015)

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Contact: severoochoa@iac.es
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