Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Aaron S. Chou
Marcelle Soares-Santos
Tim M. P. Tait
Rana X. Adhikari
Luis A. Anchordoqui
James Annis
Clarence L. Chang
Jodi Cooley
Alex Drlica-Wagner
Ke Fang
Brenna Flaugher
Joerg Jaeckel
W. Hugh Lippincott
Vivian Miranda
Laura Newburgh
Jeffrey A. Newman
Chanda Prescod-Weinstein
Gray Rybka
B. S. Sathyaprakash
David J. Schlegel
Abstract： This report summarizes the current status of Cosmic Frontier physics and the broad and exciting future prospects identified for the Cosmic Frontier as part of the 2021 Snowmass Process.
Peer Review Status:
Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Ting-Wen Lan
R. Tojeiro
E. Armengaud
J. Xavier Prochaska
T. M. Davis
David M. Alexander
A. Raichoor
Rongpu Zhou
Christophe Yeche
C. Balland
S. BenZvi
A. Berti
R. Canning
A. Carr
H. Chittenden
S. Cole
M. -C. Cousinou
K. Dawson
Biprateep Dey
K. Douglass
Abstract： The Dark Energy Spectroscopic Instrument (DESI) Survey has obtained a set of spectroscopic measurements of galaxies to validate the final survey design and target selections. To assist in these tasks, we visually inspect (VI) DESI spectra of approximately 2,500 bright galaxies, 3,500 luminous red galaxies (LRGs), and 10,000 emission line galaxies (ELGs), to obtain robust redshift identifications. We then utilize the VI redshift information to characterize the performance of the DESI operation. Based on the VI catalogs, our results show that the final survey design yields samples of bright galaxies, LRGs, and ELGs with purity greater than $99\%$. Moreover, we demonstrate that the precision of the redshift measurements is approximately 10 km/s for bright galaxies and ELGs and approximately 40 km/s for LRGs. The average redshift accuracy is within 10 km/s for the three types of galaxies. The VI process also helps improve the quality of the DESI data by identifying spurious spectral features introduced by the pipeline. Finally, we show examples of unexpected real astronomical objects, such as Ly$\alpha$ emitters and strong lensing candidates, identified by VI. These results demonstrate the importance and utility of visually inspecting data from incoming and upcoming surveys, especially during their early operation phases.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Gong-Bo Zhao
Yuting Wang
Atsushi Taruya
Weibing Zhang
Hector Gil-Marin
Arnaud de Mattia
Ashley J. Ross
Anand Raichoor
Cheng Zhao
Will J. Percival
Shadab Alam
Julian E. Bautista
Etienne Burtin
Chia-Hsun Chuang
Jiamin Hou
Kyle S. Dawson
Jean-Paul Kneib
Kazuya Koyama
Helion du Mas des Bourboux
Eva-Maria Mueller
Abstract： We perform a joint BAO and RSD analysis using the eBOSS DR16 LRG and ELG samples in the redshift range of $z\in[0.6,1.1]$, and detect a RSD signal from the cross power spectrum at a $\sim4\sigma$ confidence level, i.e., $f\sigma_8=0.317\pm0.080$ at $z_{\rm eff}=0.77$. Based on the chained power spectrum, which is a new development in this work to mitigate the angular systematics, we measurement the BAO distances and growth rate simultaneously at two effective redshifts, namely, $D_{\rm M}/r_{\rm d} \ (z=0.70)=17.96\pm0.51, \ D_{\rm H}/r_{\rm d} \ (z=0.70)=21.22\pm1.20, \ f\sigma_8 \ (z=0.70) =0.43\pm0.05$, and $D_{\rm M}/r_{\rm d} \ (z=0.845)=18.90\pm0.78, \ D_{\rm H}/r_{\rm d} \ (z=0.845)=20.91\pm2.86, \ f\sigma_8 \ (z=0.845) =0.30\pm0.08$. Combined with BAO measurements including those from the eBOSS DR16 QSO and Lyman-$\alpha$ sample, our measurement has raised the significance level of a nonzero $\Omega_{\rm \Lambda}$ to $\sim11\sigma$.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Adam D. Myers
John Moustakas
Stephen Bailey
Benjamin A. Weaver
Andrew P. Cooper
Jaime E. Forero-Romero
Bela Abolfathi
David M. Alexander
David Brooks
Edmond Chaussidon
Chia-Hsun Chuang
Kyle Dawson
Arjun Dey
Biprateep Dey
Govinda Dhungana
Peter Doel
Kevin Fanning
Enrique Gaztañaga
Satya Gontcho A Gontcho
Alma X. Gonzalez-Morales
Abstract： In 2021 May, the Dark Energy Spectroscopic Instrument (DESI) began a 5 yr survey of approximately 50 million total extragalactic and Galactic targets. The primary DESI dark-time targets are emission line galaxies (ELGs), luminous red galaxies (LRGs) and quasars (QSOs). In bright time, DESI will focus on two surveys known as the Bright Galaxy Survey (BGS) and the Milky Way Survey (MWS). DESI also observes a selection of "secondary" targets for bespoke science goals. This paper gives an overview of the publicly available pipeline (desitarget) used to process targets for DESI observations. Highlights include details of the different DESI survey targeting phases, the targeting ID (TARGETID) used to define unique targets, the bitmasks used to indicate a particular type of target, the data model and structure of DESI targeting files, and examples of how to access and use the desitarget code base. This paper will also describe "supporting" DESI target classes, such as standard stars, sky locations, and random catalogs that mimic the angular selection function of DESI targets. The DESI target selection pipeline is complex and sizable; this paper attempts to summarize the most salient information required to understand and work with DESI targeting data.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
J. Guy
S. Bailey
A. Kremin
Shadab Alam
D. M. Alexander
C. Allende Prieto
S. BenZvi
A. S. Bolton
D. Brooks
E. Chaussidon
A. P. Cooper
K. Dawson
A. de la Macorra
A. Dey
Biprateep Dey
G. Dhungana
D. J. Eisenstein
A. Font-Ribera
J. E. Forero-Romero
E. Gaztañaga
Abstract： We describe the spectroscopic data processing pipeline of the Dark Energy Spectroscopic Instrument (DESI), which is conducting a redshift survey of about 40 million galaxies and quasars using a purpose-built instrument on the 4-m Mayall Telescope at Kitt Peak National Observatory. The main goal of DESI is to measure with unprecedented precision the expansion history of the Universe with the Baryon Acoustic Oscillation technique and the growth rate of structure with Redshift Space Distortions. Ten spectrographs with three cameras each disperse the light from 5000 fibers onto 30 CCDs, covering the near UV to near infrared (3600 to 9800 Angstrom) with a spectral resolution ranging from 2000 to 5000. The DESI data pipeline generates wavelength- and flux-calibrated spectra of all the targets, along with spectroscopic classifications and redshift measurements. Fully processed data from each night are typically available to the DESI collaboration the following morning. We give details about the pipeline's algorithms, and provide performance results on the stability of the optics, the quality of the sky background subtraction, and the precision and accuracy of the instrumental calibration. This pipeline has been used to process the DESI Survey Validation data set, and has exceeded the project's requirements for redshift performance, with high efficiency and a purity greater than 99 percent for all target classes.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Jorge A. Zavala
Veronique Buat
Caitlin M. Casey
Denis Burgarella
Steven L. Finkelstein
Micaela B. Bagley
Laure Ciesla
Emanuele Daddi
Mark Dickinson
Henry C. Ferguson
Maximilien Franco
E. F. Jim'enez-Andrade
Jeyhan S. Kartaltepe
Anton M. Koekemoer
Aurélien Le Bail
E. J. Murphy
Casey Papovich
Sandro Tacchella
Stephen M. Wilkins
Itziar Aretxaga
Abstract： Lyman Break Galaxy (LBG) candidates at z>10 are rapidly being identified in JWST/NIRCam observations. Due to the (redshifted) break produced by neutral hydrogen absorption of rest-frame UV photons, these sources are expected to drop out in the bluer filters while being well detected in redder filters. However, here we show that dust-enshrouded star-forming galaxies at lower redshifts (z<7) may also mimic the near-infrared (near-IR) colors of z>10 LBGs, representing potential contaminants in LBG candidate samples. First, we analyze CEERS-DSFG-1, a NIRCam dropout undetected in the F115W and F150W filters but detected at longer wavelengths. Combining the JWST data with (sub)millimeter constraints, including deep NOEMA interferometric observations, we show that this source is a dusty star-forming galaxy (DSFG) at z~5.1. We also present a tentative 2.6sigma SCUBA-2 detection at 850um around a recently identified z~16 LBG candidate in the same field and show that, if the emission is real and associated with this candidate, the available photometry is consistent with a z~5 dusty galaxy with strong nebular emission lines despite its blue near-IR colors. Further observations on this candidate are imperative to mitigate the low confidence of this tentative submillimeter emission and its positional uncertainty. Our analysis shows that robust (sub)millimeter detections of NIRCam dropout galaxies likely imply z=4-6 redshift solutions, where the observed near-IR break would be the result of a strong rest-frame optical Balmer break combined with high dust attenuation and strong nebular line emission, rather than the rest-frame UV Lyman break. This provides evidence that DSFGs may contaminate searches for ultra high-redshift LBG candidates from JWST observations.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Rongpu Zhou
Biprateep Dey
Jeffrey A. Newman
Daniel J. Eisenstein
K. Dawson
S. Bailey
A. Berti
J. Guy
Ting-Wen Lan
H. Zou
J. Aguilar
S. Ahlen
Shadab Alam
D. Brooks
A. de la Macorra
A. Dey
G. Dhungana
K. Fanning
A. Font-Ribera
S. Gontcho A Gontcho
Abstract： The Dark Energy Spectroscopic Instrument (DESI) is carrying out a 5-year
survey that aims to measure the redshifts of tens of millions of galaxies and
quasars, including 8 million luminous red galaxies (LRGs) in the redshift range
of $0.4
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Camilla Pacifici
Kartheik G. Iyer
Bahram Mobasher
Elisabete da Cunha
Viviana Acquaviva
Denis Burgarella
Gabriela Calistro Rivera
Adam C. Carnall
Yu-Yen Chang
Nima Chartab
Kevin C. Cooke
Ciaran Fairhurst
Jeyhan Kartaltepe
Joel Leja
Katarzyna Malek
Brett Salmon
Marianna Torelli
Alba Vidal-Garcia
Mederic Boquien
Gabriel G. Brammer
Abstract： The study of galaxy evolution hinges on our ability to interpret multi-wavelength galaxy observations in terms of their physical properties. To do this, we rely on spectral energy distribution (SED) models which allow us to infer physical parameters from spectrophotometric data. In recent years, thanks to the wide and deep multi-waveband galaxy surveys, the volume of high quality data have significantly increased. Alongside the increased data, algorithms performing SED fitting have improved, including better modeling prescriptions, newer templates, and more extensive sampling in wavelength space. We present a comprehensive analysis of different SED fitting codes including their methods and output with the aim of measuring the uncertainties caused by the modeling assumptions. We apply fourteen of the most commonly used SED fitting codes on samples from the CANDELS photometric catalogs at z~1 and z~3. We find agreement on the stellar mass, while we observe some discrepancies in the star formation rate (SFR) and dust attenuation results. To explore the differences and biases among the codes, we explore the impact of the various modeling assumptions as they are set in the codes (e.g., star formation histories, nebular, dust, and AGN models) on the derived stellar masses, SFRs, and A_V values. We then assess the difference among the codes on the SFR-stellar mass relation and we measure the contribution to the uncertainties by the modeling choices (i.e., the modeling uncertainties) in stellar mass (~0.1dex), SFR (~0.3dex), and dust attenuation (~0.3mag). Finally, we present some resources summarizing best practices in SED fitting.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
David J. Setton
Biprateep Dey
Gourav Khullar
Rachel Bezanson
Jeffrey A. Newman
Jessica N. Aguilar
Steven Ahlen
Brett H. Andrews
David Brooks
Axel de la Macorra
Arjun Dey
Sarah Eftekharzadeh
Andreu Font-Ribera
Satya Gontcho A Gontcho
Anthony Kremin
Stephanie Juneau
Martin Landriau
Aaron Meisner
Ramon Miquel
John Moustakas
Abstract： We utilize $\sim17000$ bright Luminous Red Galaxies (LRGs) from the novel
Dark Energy Spectroscopic Instrument Survey Validation spectroscopic sample,
leveraging its deep ($\sim2.5$ hour/galaxy exposure time) spectra to
characterize the contribution of recently quenched galaxies to the massive
galaxy population at $0.4
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Abstract： Uncertainty quantification is crucial for assessing the predictive ability of AI algorithms. A large body of work (including normalizing flows and Bayesian neural networks) has been devoted to describing the entire predictive distribution (PD) of a target variable Y given input features $\mathbf{X}$. However, off-the-shelf PDs are usually far from being conditionally calibrated; i.e., the probability of occurrence of an event given input $\mathbf{X}$ can be significantly different from the predicted probability. Most current research on predictive inference (such as conformal prediction) concerns constructing calibrated prediction sets only. It is often believed that the problem of obtaining and assessing entire conditionally calibrated PDs is too challenging. In this work, we show that recalibration, as well as diagnostics of entire PDs, are indeed attainable goals in practice. Our proposed method relies on the idea of regressing probability integral transform (PIT) scores against $\mathbf{X}$. This regression gives full diagnostics of conditional coverage across the entire feature space and can be used to recalibrate misspecified PDs. We benchmark our corrected prediction bands against oracle bands and state-of-the-art predictive inference algorithms for synthetic data, including settings with a distributional shift. Finally, we produce calibrated PDs for two applications: (i) probabilistic nowcasting based on sequences of satellite images, and (ii) estimation of galaxy distances based on imaging data (photometric redshifts).
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Jeyhan S. Kartaltepe
Caitlin Rose
Brittany N. Vanderhoof
Elizabeth J. McGrath
Luca Costantin
Isabella G. Cox
L. Y. Aaron Yung
Dale D. Kocevski
Stijn Wuyts
Henry C. Ferguson Brett H. Andrews
Micaela B. Bagley
Steven L. Finkelstein
Ricardo O. Amorin
Pablo Arrabal Haro
Bren E. Backhaus
Peter Behroozi
Laura Bisigello
Antonello Calabro
Caitlin M. Casey
Rosemary T. Coogan
Abstract： We present a comprehensive analysis of the evolution of the morphological and structural properties of a large sample of galaxies at z=3-9 using early JWST CEERS NIRCam observations. Our sample consists of 850 galaxies at z>3 detected in both CANDELS HST imaging and JWST CEERS NIRCam images to enable a comparison of HST and JWST morphologies. Our team conducted a set of visual classifications, with each galaxy in the sample classified by three different individuals. We also measure quantitative morphologies using the publicly available codes across all seven NIRCam filters. Using these measurements, we present the fraction of galaxies of each morphological type as a function of redshift. Overall, we find that galaxies at z>3 have a wide diversity of morphologies. Galaxies with disks make up a total of 60\% of galaxies at z=3 and this fraction drops to ~30% at z=6-9, while galaxies with spheroids make up ~30-40% across the whole redshift range and pure spheroids with no evidence for disks or irregular features make up ~20%. The fraction of galaxies with irregular features is roughly constant at all redshifts (~40-50%), while those that are purely irregular increases from ~12% to ~20% at z>4.5. We note that these are apparent fractions as many selection effects impact the visibility of morphological features at high redshift. The distributions of S\'ersic index, size, and axis ratios show significant differences between the morphological groups. Spheroid Only galaxies have a higher S\'ersic index, smaller size, and higher axis ratio than Disk/Irregular galaxies. Across all redshifts, smaller spheroid and disk galaxies tend to be rounder. Overall, these trends suggest that galaxies with established disks and spheroids exist across the full redshift range of this study and further work with large samples at higher redshift is needed to quantify when these features first formed.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Rongpu Zhou
Jeffrey A. Newman
Yao-Yuan Mao
Aaron Meisner
John Moustakas
Adam D. Myers
Abhishek Prakash
Andrew R. Zentner
David Brooks
Yutong Duan
Martin Landriau
Michael E. Levi
Francisco Prada
Gregory Tarle
Abstract： We present measurements of the redshift-dependent clustering of a DESI-like luminous red galaxy (LRG) sample selected from the Legacy Survey imaging dataset, and use the halo occupation distribution (HOD) framework to fit the clustering signal. The photometric LRG sample in this study contains 2.7 million objects over the redshift range of $0.4 < z < 0.9$ over 5655 deg$^2$. We have developed new photometric redshift (photo-$z$) estimates using the Legacy Survey DECam and WISE photometry, with $\sigma_{\mathrm{NMAD}} = 0.02$ precision for LRGs. We compute the projected correlation function using new methods that maximize signal-to-noise ratio while incorporating redshift uncertainties. We present a novel algorithm for dividing irregular survey geometries into equal-area patches for jackknife resampling. For a five-parameter HOD model fit using the MultiDark halo catalog, we find that there is little evolution in HOD parameters except at the highest redshifts. The inferred large-scale structure bias is largely consistent with constant clustering amplitude over time. In an appendix, we explore limitations of Markov chain Monte Carlo fitting using stochastic likelihood estimates resulting from applying HOD methods to N-body catalogs, and present a new technique for finding best-fit parameters in this situation. Accompanying this paper we have released the Photometric Redshifts for the Legacy Surveys (PRLS) catalog of photo-$z$'s obtained by applying the methods used in this work to the full Legacy Survey Data Release 8 dataset. This catalog provides accurate photometric redshifts for objects with $z < 21$ over more than 16,000 deg$^2$ of sky.
Peer Review Status:Awaiting Review
Hits
Hits
Downloads
Comment