16 research outputs found
VIPERS: Stellar population properties of early-type galaxies
We present stellar population properties of early-type galaxies from the VIMOS Public Extragalactic Redshift Survey (VIPERS) based on the spectral measurements of ∼ 4000 galaxies with stellar masses from 10^{10} to 10^{12} {[M_{☉}]} in the redshift range 0.4 < z < 1.0. We quantify relations between their age, stellar metallicity, duration of star burst, and stellar mass. We compare the properties of VIPERS intermediate redshift galaxies with galaxies found in the Local Universe
PROVABGS: The Probabilistic Stellar Mass Function of the BGS One-percent Survey
We present the probabilistic stellar mass function (pSMF) of galaxies in the DESI Bright Galaxy Survey (BGS), observed during the One-percent Survey. The One-percent Survey was one of DESI’s survey validation programs conducted from 2021 April to May, before the start of the main survey. It used the same target selection and similar observing strategy as the main survey and successfully observed the spectra and redshifts of 143,017 galaxies in the r 100 × more galaxies. Moreover, we present the statistical framework for subsequent population statistics measurements using BGS, which will characterize the global galaxy population and scaling relations at low redshifts with unprecedented precision
Changing-look Active Galactic Nuclei from the Dark Energy Spectroscopic Instrument. I. Sample from the Early Data
Changing-look active galactic nuclei (CL AGNs) can be generally confirmed by the emergence (turn-on) or disappearance (turn-off) of broad emission lines (BELs), associated with a transient timescale (about 100 ∼ 5000 days) that is much shorter than predicted by traditional accretion disk models. We carry out a systematic CL AGN search by crossmatching the spectra coming from the Dark Energy Spectroscopic Instrument and the Sloan Digital Sky Survey. Following previous studies, we identify CL AGNs based on Hα, Hβ, and Mg ii at z ≤ 0.75 and Mg ii, C iii], and C iv at z > 0.75. We present 56 CL AGNs based on visual inspection and three selection criteria, including 2 Hα, 34 Hβ, 9 Mg ii, 18 C iii], and 1 C iv CL AGN. Eight cases show simultaneous appearances/disappearances of two BELs. We also present 44 CL AGN candidates with significant flux variation of BELs, but remaining strong broad components. In the confirmed CL AGNs, 10 cases show additional CL candidate features for different lines. In this paper, we find: (1) a 24:32 ratio of turn-on to turn-off CL AGNs; (2) an upper-limit transition timescale ranging from 330 to 5762 days in the rest frame; and (3) the majority of CL AGNs follow the bluer-when-brighter trend. Our results greatly increase the current CL census (∼30%) and would be conducive to exploring the underlying physical mechanism
PROVABGS: The Probabilistic Stellar Mass Function of the BGS One-Percent Survey
We present the probabilistic stellar mass function (pSMF) of galaxies in the
DESI Bright Galaxy Survey (BGS), observed during the One-Percent Survey. The
One-Percent Survey was one of DESI's survey validation programs conducted from
April to May 2021, before the start of the main survey. It used the same target
selection and similar observing strategy as the main survey and successfully
observed the spectra and redshifts of 143,017 galaxies in the
magnitude-limited BGS Bright sample and 95,499 galaxies in the fainter surface
brightness and color selected BGS Faint sample over . We derive pSMFs
from posteriors of stellar mass, , inferred from DESI photometry and
spectroscopy using the Hahn et al. (2022a; arXiv:2202.01809) PRObabilistic
Value-Added BGS (PROVABGS) Bayesian SED modeling framework. We use a
hierarchical population inference framework that statistically and rigorously
propagates the uncertainties. Furthermore, we include correction weights
that account for the selection effects and incompleteness of the BGS
observations. We present the redshift evolution of the pSMF in BGS as well as
the pSMFs of star-forming and quiescent galaxies classified using average
specific star formation rates from PROVABGS. Overall, the pSMFs show good
agreement with previous stellar mass function measurements in the literature.
Our pSMFs showcase the potential and statistical power of BGS, which in its
main survey will observe >100 more galaxies. Moreover, we present the
statistical framework for subsequent population statistics measurements using
BGS, which will characterize the global galaxy population and scaling relations
at low redshifts with unprecedented precision.Comment: 25 pages, 12 figures; data used to generate figures is available at
https://doi.org/10.5281/zenodo.8018936; submitted to Ap
DESI Survey Validation Spectra Reveal an Increasing Fraction of Recently Quenched Galaxies at z ∼ 1
Full list of authors: Setton, David J.; Dey, Biprateep; Khullar, Gourav; Bezanson, Rachel; Newman, Jeffrey A.; Aguilar, Jessica N.; Ahlen, Steven; Andrews, Brett H.; Brooks, David; de la Macorra, Axel; Dey, Arjun; Eftekharzadeh, Sarah; Font-Ribera, Andreu; Gontcho, Satya Gontcho; Kremin, Anthony; Juneau, Stephanie; Landriau, Martin; Meisner, Aaron; Miquel, Ramon; Moustakas, John; Pearl, Alan; Prada, Francisco; Tarle, Gregory; Siudek, Malgorzata; Weaver, Benjamin Alan; Zhou, Zhimin; Zou, Hu.--This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.We utilize ∼17,000 bright luminous red galaxies (LRGs) from the novel Dark Energy Spectroscopic Instrument Survey Validation spectroscopic sample, leveraging its deep (∼2.5 hr galaxy−1 exposure time) spectra to characterize the contribution of recently quenched galaxies to the massive galaxy population at 0.4 1) of our sample of recently quenched galaxies represents the largest spectroscopic sample of post-starburst galaxies at that epoch. At 0.4 11.2) LRGs by measuring the fraction of stellar mass each galaxy formed in the gigayear before observation, f1 Gyr. Although galaxies with f1 Gyr > 0.1 are rare at z ∼ 0.4 (≲0.5% of the population), by z ∼ 0.8, they constitute ∼3% of massive galaxies. Relaxing this threshold, we find that galaxies with f1 Gyr > 5% constitute ∼10% of the massive galaxy population at z ∼ 0.8. We also identify a small but significant sample of galaxies at z = 1.1–1.3 that formed with f1 Gyr > 50%, implying that they may be analogs to high-redshift quiescent galaxies that formed on similar timescales. Future analysis of this unprecedented sample promises to illuminate the physical mechanisms that drive the quenching of massive galaxies after cosmic noon. © 2023. The Author(s). Published by the American Astronomical Society.This research is supported by the Director, Office of Science, Office of High Energy Physics of the U.S. Department of Energy under contract No. DE-AC02-05CH11231 and by the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility under the same contract. Additional support for DESI is provided by the U.S. National Science Foundation, Division of Astronomical Sciences under contract No. AST-0950945 to the NSF's National Optical-Infrared Astronomy Research Laboratory; the Science and Technologies Facilities Council of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the French Alternative Energies and Atomic Energy Commission (CEA); the National Council of Science and Technology of Mexico (CONACYT); the Ministry of Science and Innovation of Spain (MICINN); and the DESI member institutions: https://www.desi.lbl.gov/collaborating-institutions. D.S. gratefully acknowledges support from NSF-AAG No. 1907697 and the PITT PACC graduate fellowship. The published results were also funded by the Polish National Agency for Academic Exchange (Bekker grant BPN/BEK/2021/1/00298/DEC/1), the European Union's Horizon 2020 research and innovation program under the Maria Skłodowska-Curie (grant agreement No. 754510), and the Spanish Ministry of Science and Innovation through the Juan de la Cierva-formacion program (reference FJC2018-038792-I).With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).Peer reviewe
Depresja u chorych na reumatoidalne zapalenie stawów
Depresja jest najczęstszym schorzeniem psychicznym występującymu pacjentów tzw. podstawowej opieki zdrowotnej i stwierdzasię ją u 12,5% chorych, a w przebiegu schorzeń przewlekłych jestroz poznawana wielokrotnie częściej.Do rozwoju depresji w przebiegu schorzeń przewlekłych przyczyniasię wiele czynników, takich jak: predyspozycje genetyczne, predyspozycjepsychiczne, długotrwale utrzymujący się stres orazzwiększenie stężeń cytokin prozapalnych w ośrodkowym układzienerwowym. Ośrodkowy układ nerwowy w wyniku działania cytokinprozapalnych aktywuje wiele zmian w układzie neuroendokrynnymi immunologicznym, określanych jako „zachowanie chorobowe” (sickness behaviour).W reumatoidalnym zapaleniu stawów (RZS) depresja występujeu 13–65% chorych, ale tylko u 25% chorych jest rozpoznana. Tak częstewystępowanie depresji jest wynikiem utrzymywania się dużegostężenia cytokin prozapalnych wtym schorzeniu, powodującego zaburzeniaw zachowaniu. Depresja wpływa negatywnie na przebieg RZS,nasilając objawy somatyczne choroby. Z kolei wyniki leczenia depresjisą tym gorsze, im większa jest aktywność RZS, co powoduje zmniejszenieskuteczności leczenia podtrzymującego i zwiększa możliwośćwy stąpienia nawrotów depresji po pierwszym epizodzie. Udowadniato konieczność jednoczesnego intensywnego leczenia obu chorób i ichwczesnego rozpoznania. Rozpoznanie depresji może nastręczać dużotrudności z powodu nakładania się objawów wy stępujących zarównow depresji, jak i w RZS, takich jak: zmęczenie, brak apetytu, zmniejszeniemasy ciała, różnego typu dolegliwości bólowe itp. Nierozpoznanadepresja w przebiegu RZS, poza wpływem na nasilenie objawówchoroby, zmniejsza skuteczność stosowanej terapii, z uwagi na gorsząwspółpracę pacjenta i mniejsze zaangażowanie w leczenie. Zwiększato ryzyko myśli i prób samobójczych oraz skraca czas przeżycia pacjentówchorych na RZS
Red Nuggets - Hunting for Untouched Survivors from the Early Universe
International audienceIn order to understand the history of our Universe we attempt to trace different stages of evolution of different types of galaxies as a function of time. While we can easily detect and analyze sources at low redshift, at high redshift we face strong barriers due to the resolution and detection limits. Now, we finally have an opportunity to see those objects due to the technical progress of astronomical instruments. Recently, astronomers found a new population of compact and massive galaxies - ''red nuggets''. These specific objects are believed to evolve undisturbed from early cosmic epochs and represent a unique laboratory to study how the first massive galaxies formed and evolved. Here, we present the process of searching for the red nuggets in the sample of ∼90 k galaxies in VIPERS, a spectroscopic survey at redshift 0.5 < z <1.2. We present currently the largest sample of 77 red nugget candidates at redshift z ∼ 0.7
Red Nuggets - Hunting for Untouched Survivors from the Early Universe
International audienceIn order to understand the history of our Universe we attempt to trace different stages of evolution of different types of galaxies as a function of time. While we can easily detect and analyze sources at low redshift, at high redshift we face strong barriers due to the resolution and detection limits. Now, we finally have an opportunity to see those objects due to the technical progress of astronomical instruments. Recently, astronomers found a new population of compact and massive galaxies - ''red nuggets''. These specific objects are believed to evolve undisturbed from early cosmic epochs and represent a unique laboratory to study how the first massive galaxies formed and evolved. Here, we present the process of searching for the red nuggets in the sample of ∼90 k galaxies in VIPERS, a spectroscopic survey at redshift 0.5 < z <1.2. We present currently the largest sample of 77 red nugget candidates at redshift z ∼ 0.7
Automatic classification of sources in large astronomical catalogs
In this paper we address two questions related to data analysis in large astronomical datasets, and we demonstrate how they can be answered making use of machine learning techniques. The first question is: how to efficiently find previously unknown or rare objects which can be expected to exist in big data samples? Using the largest existing extragalactic all-sky survey, provided by the WISE satellite, we demonstrate that, surprisingly, supervised classification methods can come to aid. The second question is: having a sufficiently large data sample, how can we look for new optimal classification schemes, possibly finding new and previously unknown classes and subclasses of sources? Based on the VIPERS cutting-edge galaxy catalog at redshift z > 0.5, we demonstrate that unsupervised classification methods can give unexpected but physically well-motivated results