Zeljko Ivezic
University of Washington
H-index: 142
North America-United States
Description
Zeljko Ivezic, With an exceptional h-index of 142 and a recent h-index of 80 (since 2020), a distinguished researcher at University of Washington, specializes in the field of astrophysics.
His recent articles reflect a diverse array of research interests and contributions to the field:
The Quasar Catalogue for S-PLUS DR4 (QuCatS) and the estimation of photometric redshifts
The XXL survey-LII. The evolution of radio AGN LF determined via parametric methods from GMRT, ATCA, VLA, and Cambridge interferometer observations
The XXL survey LII: The evolution of radio AGN luminosity function determined via parametric methods from GMRT, ATCA, VLA and Cambridge interferometer observations
Detecting Long-period Variability in the SDSS Stripe 82 Standards Catalog
Simulating the Legacy Survey of Space and Time Stellar Content with TRILEGAL
MUSSES2020J: the earliest discovery of a fast blue ultraluminous transient at redshift 1.063
Periodically variable quasar candidates in SDSS Stripe 82 region
Simulated SPHEREx spectra of asteroids and their implications for asteroid size and reflectance estimation
Professor Information
University | University of Washington |
---|---|
Position | ___ |
Citations(all) | 131071 |
Citations(since 2020) | 38121 |
Cited By | 108332 |
hIndex(all) | 142 |
hIndex(since 2020) | 80 |
i10Index(all) | 300 |
i10Index(since 2020) | 222 |
University Profile Page | University of Washington |
Research & Interests List
astrophysics
Top articles of Zeljko Ivezic
The Quasar Catalogue for S-PLUS DR4 (QuCatS) and the estimation of photometric redshifts
The advent of massive broad-band photometric surveys enabled photometric redshift estimates for unprecedented numbers of galaxies and quasars. These estimates can be improved using better algorithms or by obtaining complementary data such as narrow-band photometry, and broad-band photometry over an extended wavelength range. We investigate the impact of both approaches on photometric redshifts for quasars using data from S-PLUS DR4, GALEX DR6/7, and unWISE in three machine learning methods: Random Forest (RF), FlexCoDE, and Bayesian Mixture Density Network (BMDN). Including narrow-band photometry improves the root-mean-square error by 11% in comparison to a model trained with only broad-band photometry. Narrow-band information only provided an improvement of 3.8% when GALEX and WISE colours were included. Thus narrow bands play a more important role for …
Authors
L Nakazono,RR Valença,G Soares,R Izbicki,Ž Ivezić,EVR Lima,NST Hirata,L Sodré Jr,R Overzier,F Almeida-Fernandes,GB Oliveira Schwarz,W Schoenell,A Kanaan,T Ribeiro,C Mendes de Oliveira
Journal
Monthly Notices of the Royal Astronomical Society
Published Date
2024/4/9
The XXL survey-LII. The evolution of radio AGN LF determined via parametric methods from GMRT, ATCA, VLA, and Cambridge interferometer observations
We model the evolution of active galactic nuclei (AGN) by constructing their radio LFs. We used a set of surveys of varying area and depth, namely, the deep COSMOS survey of 1916 AGN sources; the wide, shallow 3CRR, 7C, and 6CE surveys, together containing 356 AGN; and the intermediate XXL-North and South fields consisting of 899 and 1484 sources, respectively. We also used the CENSORS, BRL, Wall & Peacock, and Config surveys, respectively consisting of 150, 178, 233, and 230 sources. Together, these surveys account for 5446 AGN sources and constrained the LFs at high redshift and over a wide range of luminosities (up to z ≈ 3 and log(L/W Hz−1)∈[22, 29]). We concentrated on parametric methods within the Bayesian framework, which allowed us to perform model selection between a set of different models. By comparing the marginalised likelihoods and both the Akaike information …
Authors
Bruno Šlaus,Vernesa Smolčić,Željko Ivezić,S Fotopoulou,CJ Willott,P Pendo,C Vignali,L Chiappetti,M Pierre
Journal
Astronomy & astrophysics
Published Date
2024/4/1
The XXL survey LII: The evolution of radio AGN luminosity function determined via parametric methods from GMRT, ATCA, VLA and Cambridge interferometer observations
We model the evolution of active galactic nuclei by constructing their radio luminosity functions. We use a set of surveys of varying area and depth, namely the deep COSMOS survey of AGN sources, the wide shallow 3CRR, 7C and 6CE surveys, containing together AGNs, and the intermediate XXL-North and South fields consisting of and sources, respectively. We also used the CENSORS, BRL, Wall Peacock and Config surveys, consisting respectively of , , and sources. Together, these surveys numbered AGN sources and constrained the luminosity functions at high redshift and over a wide range of luminosities (up to and . We concentrate on parametric methods within the Bayesian framework and show that the luminosity-dependent density evolution (LDDE) model fits the data best, with evidence ratios varying from "strong" () to "decisive" () according to the Jeffreys interpretation. We determine the number density, luminosity density and kinetic luminosity density as a function of redshift, and observe a flattening of these functions at higher redshifts, not present in simpler models, which we explain by our use of the LDDE model. Finally, we divide our sample into subsets according to the stellar mass of the host galaxies in order to investigate a possible bimodality in evolution. We found a difference in LF shape and evolution between these subsets. All together, these findings point to a physical picture where the evolution and density of AGN cannot be explained well by simple models but require more complex models either via AGN sub-populations where the total AGN …
Authors
B Šlaus,V Smolcic,Ž Ivezic,S Fotopoulou,CJ Willott,P Pendo,C Vignali,L Chiappetti,M Pierre
Journal
arXiv preprint arXiv:2312.14683
Published Date
2023/12/22
Detecting Long-period Variability in the SDSS Stripe 82 Standards Catalog
We report the results of a search for long-period (100< P< 600 days) periodic variability in the SDSS Stripe 82 standards catalog. The SDSS coverage of Stripe 82 enables such a search because there are on average 20 observations per band in ugriz bands for about one million sources, collected over about 6 yr, with a faint limit of r∼ 22 mag and precisely calibrated 1%–2% photometry. We calculated the periods of variable source candidates in this sample using the Lomb–Scargle periodogram and considered the three highest periodogram peaks in each of the gri filters as relevant. Only those sources with gri periods consistent within 0.1% were later studied. We use the Kuiper statistic to ensure uniform distribution of data points in phased light curves. We present five sources with the spectra consistent with quasar spectra and plausible periodic variability. This SDSS-based search bodes well for future sensitive …
Authors
Marta Fatović,Lovro Palaversa,Krešimir Tisanić,Karun Thanjavur,Željko Ivezić,Andjelka B Kovačević,Dragana Ilić,Luka Č Popović
Journal
The Astronomical Journal
Published Date
2023/3/1
Simulating the Legacy Survey of Space and Time Stellar Content with TRILEGAL
We describe a large simulation of the stars to be observed by the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). The simulation is based on the TRILEGAL code, which resorts to large databases of stellar evolutionary tracks, synthetic spectra, and pulsation models, added to simple prescriptions for the stellar density and star formation histories of the main structures of the Galaxy, to generate mock stellar samples through a population synthesis approach. The main bodies of the Magellanic Clouds are also included. A complete simulation is provided for single stars, down to the r= 27.5 mag depth of the coadded Wide–Fast–Deep survey images. A second simulation is provided for a fraction of the binaries, including the interacting ones, as derived with the BinaPSE module of TRILEGAL. We illustrate the main properties and numbers derived from these simulations, including: comparisons with …
Authors
Piero Dal Tio,Giada Pastorelli,Alessandro Mazzi,Michele Trabucchi,Guglielmo Costa,Alice Jacques,Adriano Pieres,Léo Girardi,Yang Chen,Knut AG Olsen,Mario Juric,Željko Ivezić,Peter Yoachim,William I Clarkson,Paola Marigo,Thaise S Rodrigues,Simone Zaggia,Mauro Barbieri,Yazan Momany,Alessandro Bressan,Robert Nikutta,Luiz Nicolaci da Costa
Journal
The Astrophysical Journal Supplement Series
Published Date
2022/8/26
MUSSES2020J: the earliest discovery of a fast blue ultraluminous transient at redshift 1.063
In this Letter, we report the discovery of an ultraluminous fast-evolving transient in rest-frame UV wavelengths, MUSSES2020J, soon after its occurrence by using the Hyper Suprime-Cam (HSC) mounted on the 8.2 m Subaru telescope. The rise time of about 5 days with an extremely high UV peak luminosity shares similarities to a handful of fast blue optical transients whose peak luminosities are comparable with the most luminous supernovae while their timescales are significantly shorter (hereafter" fast blue ultraluminous transient," FBUT). In addition, MUSSES2020J is located near the center of a normal low-mass galaxy at a redshift of 1.063, suggesting a possible connection between the energy source of MUSSES2020J and the central part of the host galaxy. Possible physical mechanisms powering this extreme transient such as a wind-driven tidal disruption event and an interaction between supernova and …
Authors
Ji-an Jiang,Naoki Yasuda,Keiichi Maeda,Nozomu Tominaga,Mamoru Doi,Željko Ivezić,Peter Yoachim,Kohki Uno,Takashi J Moriya,Brajesh Kumar,Yen-Chen Pan,Masayuki Tanaka,Masaomi Tanaka,Ken’ichi Nomoto,Saurabh W Jha,Pilar Ruiz-Lapuente,David Jones,Toshikazu Shigeyama,Nao Suzuki,Mitsuru Kokubo,Hisanori Furusawa,Satoshi Miyazaki,Andrew J Connolly,DK Sahu,GC Anupama
Journal
The Astrophysical Journal Letters
Published Date
2022/7/12
Periodically variable quasar candidates in SDSS Stripe 82 region
We report the results of a search for small-amplitude (A less than 0.3 mag) long-period (P longer than 100 days) sources with periodic variability in SDSS Stripe 82 region. The SDSS coverage of Stripe 82 enables such a search because there are on average 20 observations per band in ugriz bands for about 1 million stars, collected over about 6 years, with a faint limit of r∼ 22 mag and precisely calibrated 1-2% photometry. We calculated the periods of candidate variable sources in this sample using the LombScargle periodogram and considered the three highest periodogram peaks in each of the gri filters as relevant. Only those sources with gri periods consistent to within 0.1% were later studied. We focus our search on periodic variables with periods 100< P< 600 days and uniform distribution of data points in phased light curves. We present 10 plausible candidates out of which seven have available archival spectra (two consistent with stars and five consistent with quasars). We have thoroughly analised the periodicity and photometry of the five plausibly periodically variable quasars, specifically focusing on possible false periods originating from the stochastic quasar variability. Furthermore, we extended the observational baseline of the SDSS with additional epochs from the ZTF and Pan-STARRS. The new data are in agreement with our model. Multiple explanations for the observed periodic behaviour are found in the literature: radio jet precession, tilted or warped accretion disks, but most of the explanations include binary super-massive black hole (BSMBH) systems. We single out one quasar with a period of P= 278 days whose X-ray …
Authors
Marta Fatović,Lovro Palaversa,Krešimir Tisanić,Karun Thanjavur,Željko Ivezić
Published Date
2022
Simulated SPHEREx spectra of asteroids and their implications for asteroid size and reflectance estimation
We describe the construction and analysis of simulated SPHEREx spectra of Main Belt and Trojan asteroids. SPHEREx will deliver the first all-sky spectral survey at 96 spectral channels between 0.75 μ m and 5.0 μ m. We have developed a method for correcting SPHEREx asteroid spectra for intrinsic rotational variability that does not require light curves and can enable studies before LSST light curves become available for this purpose. Using these spectra, we predict that SPHEREx will deliver meaningful flux measurements for about 100,000 asteroids, including close to 10,000 objects with high-quality spectra; this dataset will represent an increase over our current sample size by more than an order of magnitude. The main SPHEREx contribution to asteroid science will be derived from taxonomic classifications, detailed spectroscopic analyses involving a number of diagnostic spectral features associated with …
Authors
Željko Ivezić,Vedrana Ivezić,Joachim Moeyens,Carey M Lisse,Schelte J Bus,Lynne Jones,Brendan P Crill,Olivier Doré,Joshua P Emery
Journal
Icarus
Published Date
2022/1/1
Professor FAQs
What is Zeljko Ivezic's h-index at University of Washington?
The h-index of Zeljko Ivezic has been 80 since 2020 and 142 in total.
What are Zeljko Ivezic's top articles?
The articles with the titles of
The Quasar Catalogue for S-PLUS DR4 (QuCatS) and the estimation of photometric redshifts
The XXL survey-LII. The evolution of radio AGN LF determined via parametric methods from GMRT, ATCA, VLA, and Cambridge interferometer observations
The XXL survey LII: The evolution of radio AGN luminosity function determined via parametric methods from GMRT, ATCA, VLA and Cambridge interferometer observations
Detecting Long-period Variability in the SDSS Stripe 82 Standards Catalog
Simulating the Legacy Survey of Space and Time Stellar Content with TRILEGAL
MUSSES2020J: the earliest discovery of a fast blue ultraluminous transient at redshift 1.063
Periodically variable quasar candidates in SDSS Stripe 82 region
Simulated SPHEREx spectra of asteroids and their implications for asteroid size and reflectance estimation
...
are the top articles of Zeljko Ivezic at University of Washington.
What are Zeljko Ivezic's research interests?
The research interests of Zeljko Ivezic are: astrophysics
What is Zeljko Ivezic's total number of citations?
Zeljko Ivezic has 131,071 citations in total.
What are the co-authors of Zeljko Ivezic?
The co-authors of Zeljko Ivezic are Timothy Heckman, Gillian Knapp, Max Tegmark, Neta Bahcall, Gordon Richards, David W Hogg.