We know that approximately half of the total amount of energy emitted by the universe since the big bang has been absorbed by dust and re-radiated between 60μm and 500μm. The lack of surveys in this range leaves an open question: ”were these types of galaxies (with a high star formation rate at the highest luminosities) more common or more luminous in the past?”. This is one of the questions that I will try to answer in this seminar.
We selected, from one of the largest surveys performed with the Herschel Space Observatory, 320 galaxies representative of the total sample, and we applied to it a spectral energy distribution fitting code, CIGALE.
This method performs according to a set of defined parameters, a bayesian analysis that minimize the chi square recovered from the different fits. We compared the Dust Mass (given in solar mass), the dust luminosity (given in solar luminosity), the star formation rate (in solar masses per year), the stellar mass (given in solar mass per year) with previous works: Pappalardo et al. 2016, Smith et al. 2012, and the Da Cunha et al. 2010. The dust mass is, in our sample, higher with respect the other works as is the case for the star formation rate but with a closer resemblance to Pappalardo et al. 2016. For the other three parameters we found the opposite, with lower results than the other works. We drew three plots analysing the SFR with respect to the stellar mass, the dust luminosity and the dust mass. What we found, comparing our results with the works mentioned above, was that we had lower values for our parameters but similar shapes in the respective plots.
The similarities between our work and Pappalardo et al. are a confirmation that we are observing similar galaxies. We find a linear correlation between the dust luminosity and the star formation rate, in agreement with previous results and we found that the H-ATLAS survey is able to investigate dusty galaxies at reasonable redshift range.
Our results show that a future analysis with this survey may perform an accurate estimation of the dust evolution in nearby Universe.
2017 July 24, 09:00
Faculdade de CiÍncias da Universidade de Lisboa (C1.4.14)
Campo Grande, 1749-016 Lisboa