Found 20 talks width keyword SDSS

Tuesday May 25, 2021
Drs. Olga Mena


In this talk, we shall review the impact of the neutrino properties on the different cosmological observables. We shall also present the latest cosmological constraints on the neutrino masses and on the effective number of relativistic species. Special attention would be devoted to the role of neutrinos in solving the present cosmological tensions.

Thursday December 12, 2019
Dr. Marc Pinsonneault
Ohio State university


Time-domain space missions have revolutionized our understanding of stellar physics and stellar populations. Virtually all evolved stars can be detected as oscillators in missions such as Kepler, K2, TESS and PLATO.  Asteroseismology, or the study of stellar oscillations, can be combined with spectroscopy to infer masses, radii and ages for very large samples of stars.  This asteroseismic data can also be used to train machine learning tools to infer ages for even larger stellar population studies, sampling a large fraction of the volume of the Milky Way galaxy. In this talk I demonstrate that asteroseismic radii are in excellent agreement with those inferred using Gaia and spectroscopic data; this demonstrates that the current asteroseismic data is precise and accurate at the 1-2% level.  Major new catalogs for Kepler and K2 data are nearing completion, and I present initial results from both. We find unexpected age patterns in stars though to be chemically old, illustrating the power of age information for Galactic archeology.  Prospects for future progress in the TESS era will also be discussed.

Thursday June 13, 2019
Dr. Jorge Sanchez Almeida


Although the name 'fundamental metallicity relation' (FMR) may sound a bit bombastic, it really represents a fundamental relation in the sense of revealing a fundamental process in galaxy formation. Numerical simulations predict that accretion of cosmic web gas feeds star formation in star-forming galaxies. However, this solid theoretical prediction has been extremely elusive to confirm. The FMR, i.e., the fact that galaxies of the same stellar mass but larger star formation rate (SFR) tend to have smaller gas-phase metallicity (Zg), is one of the best observational supports available yet. The talk will introduce the FMR and then present recent results of our group showing how the FMR emerges from a local anti-correlation between SFR and Zg existing in the disks of galaxies. Thus, understanding the FMR is equivalent to understanding why active star-forming regions tend to have low relative metallicity. The existence of the local anti-correlation SFR-vs-Zg is found by Sanchez-Menguiano+19 ApJ  and Sanchez Almeida+18 MNRAS, whereas the equivalence between local and global laws is in Sanchez Almeida & Sanchez-Menguiano 19 ApJL.

Tuesday April 9, 2019
Dr. Jose Sánchez Gallego
Univ. of Washington, Seattle


The Sloan Digital Sky Survey (SDSS) is one of the most successful and prolific projects in the history of Astronomy.
In its fifth iteration SDSS-V (2020-2025) will provide a more comprehensive, global picture of the local universe by
studying the interplay between galactic genesis, stellar and black hole processes, and the physics of the ISM. I will
review the main science goals of the project, the exciting new hardware being implemented (robot fibre positioner,
large IFU systems), and the operational challenges. As in its previous incarnations, SDSS-V remains committed to
providing high-quality data products for the astronomical and educational communities. I will discuss some of the
new ideas being developed for SDSS-V with regards to data reduction, release, archival, and visualisation.

Thursday March 14, 2019
Prof. Jon Holtzman
Fundacion Jesus Serra


The SDSS Apache Point Observatory Galactic Evolution 
Experiment (APOGEE) has
collected high resolution near-IR spectra of several hundred thousand stars
across the Milky Way. I'll describe some observational results about the
spatial variation of chemical abundances as a function of Galactocentric
radius and distance from the midplane, discussing mean abundances, 
distribution function, and the variation of abundance ratios of multiple
elements. Additional information related to stellar ages can be obtained
from [C/N] for red giant stars. Several lines of evidence suggest that 
migration has had a significant impact on the Galactic disk. The 
observed patterns of
abundance ratios may provide observational constraints on 
nucleosynthetic yields.

Tuesday April 28, 2015
Dr. Carlos Allende


SDSS-III and its four surveys, BOSS, SEGUE-2, MARVELS and APOGEE, came to an end in June 2014, and all data were publicly released last January. The IAC participation as a full member spanned all surveys, and has driven an increase in the use of SDSS data at the IAC: about 15 % of the papers published by the IAC (and about 30% of its citations) in 2010-2014 involve the use of SDSS data.SDSS-IV started immediately after SDSS-III ended, with three new surveys, eBOSS, APOGEE-2, and MaNGA. The IAC continues in the collaboration as the sole full institutional member in Spain, and one of the few in Europe. We will provide an update on SDSS-IV, and bring some the IAC researchers working on SDSS to tell us first hand about their science.

Tuesday March 18, 2014
Dr. Carlos Allende, Dr. Ismael Pérez Forunon
Instituto de Astrofisica de Canarias


The IAC is the only Spanish Institution participating as a full member in SDSS-III (2009-2014). The survey finishes in June 2014, and will publicly release all data by the end of the year, including H-band high-resolution spectra for 100,000 stars in the Milky Way and optical mid-resolution spectra for 1.5 million LRGs and 160,000 quasars.

SDSS-IV will immediately follow, including spectroscopic surveys of variable sources, x-ray source follow-up observations, galaxy and quasar redshifts, Integral-field-unit spectroscopy of galaxies and high-resolution infrared spectroscopy of galactic stars, organized in the following projects: Time-Domain Spectroscopic Survey (TDSS), SPectroscopic IDentification of ERosita Sources (SPIDERS), Extended Baryon Oscillation Spectroscopic Survey (eBOSS), Mapping Nearby Galaxies at APO (MaNGA), and the APO Galaxy Evolution Experiment 2 (APOGEE-2).

The participation of the IAC in SDSS is gaining strength. As an example, in the first half of 2013, about 13% of the papers published by IAC researchers used SDSS data, and these papers contributed 33% of the citations received by the IAC in the same period. We will provide an overview of SDSS activities at the IAC, and current plans for participating in SDSS-IV (2014-2020).

Thursday December 5, 2013
Dr. Sandesh Kulkarni
MPIE, Garching, Germany


 How does the group environment hamper star-formation in star-forming galaxies?

Abstract: We present the first results from the H-alpha Galaxy Groups Imaging Survey (HAGGIS), a narrow-band imaging survey of SDSS groups at z < 0.05 conducted using the Wide Field Imager (WFI) on the ESO/MPG 2.2 meter telescope and the Wide Field Camera (WFC) on the Issac Newton Telescope (INT). In total, we observed 100 galaxy groups with wide range of halo mass 10^12 - 10^14 M_sun in pairs of narrow-band filters selected to get continuum subtracted rest-frame H-alpha images for each galaxy in these groups. The excellent data allows us to detect H-alpha down to the 10^(-18) ergs/s/cm^2/arcsec^2 level. Here, we examine the role played by halo mass and galaxy stellar mass in deciding the overall star formation activity in star forming disks by comparing stacked H-alpha profiles of galaxies in different halo mass and stellar mass bins. With this preliminary study, we have found that the star-formation activity in star-forming galaxies decreases in larger halos compared to the field galaxies. Using median equivalent width profiles, we can infer how environmental processes affect star-forming galaxies differently at different radii.

Tuesday March 5, 2013
Drs. Carlos Allende, Ismael Perez Fournon


This has been an exciting year for the SDSS-III collaboration. BOSS has made spectacular progress and it is running 6 months ahead of schedule. APOGEE has secured ~ 300,000 spectra for 50,000 stars, mostly red giants and nearly half of its total sample. The APOGEE Stellar Parameter and Chemical Abundance Pipeline is providing reliable atmospheric parameters, including metallicities. Data Release 10 (DR10) will take place next summer, but DR10 BOSS data are already available to the collaboration, and DR10 APOGEE data products will be internally released in the next few weeks. SDSS activity is growing at the IAC. We will report on SDSS-III news and SDSS-IV prospects, including an overview of the SDSS-IV programs APOGEE-2, eBOSS (+TDSS+SPIDERS), and MaNGA.

Tuesday February 7, 2012
Dr. Carlos Allende, Dr. Ismael Pérez Fournon


The IAC started in June 2010 its participation as an institutional member in the current phase of the Sloan Digital Sky Survey (SDSS-III). In the last year there has been plenty of news in all four projects of the survey: BOSS, MARVELS, SEGUE-2 and APOGEE. In this talk we will summarize the main results, give a progress report, describe the next public data release (DR9), and highlight the contributions and involvement at the IAC. SDSS-III will end in 2014, and we will provide a glimpse of what is coming up afterward.

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