The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All of the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 deg2 of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 stars from the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include the measured abundances of 15 different elements for each star. In total, SDSS-III added 5200 deg2 of ugriz imaging; 155,520 spectra of 138,099 stars as part of the Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey; 2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216 stars over 9376 deg2; 618,080 APOGEE spectra of 156,593 stars; and 197,040 MARVELS spectra of 5513 stars. Since its first light in 1998, SDSS has imaged over 1/3 of the Celestial sphere in five bands and obtained over five million astronomical spectra.
Nandini Sahu, Anowar J. Shajib, Kim-Vy Tran
et al.
Strong gravitational lenses with two background sources at widely separated redshifts are a powerful and independent probe of cosmological parameters. We can use these systems, known as Double-Source-Plane Lenses (DSPLs), to measure the ratio ($β$) of angular-diameter distances of the sources, which is sensitive to the matter density ($Ω_m$) and the equation-of-state parameter for dark-energy ($w$). However, DSPLs are rare and require high-resolution imaging and spectroscopy for detection, lens modeling, and measuring $β$. Here we report only the second DSPL ever used to measure cosmological parameters. We model the DSPL AGEL150745+052256 from the ASTRO 3D Galaxy Evolution with Lenses (AGEL) survey using HST/WFC3 imaging and Keck/KCWI spectroscopy. The spectroscopic redshifts for the deflector and two sources in AGEL1507 are $z_{\rm defl}=0.594$, $z_{\rm S1}=2.163$, and $z_{\rm S2}=2.591$. We measure a stellar velocity dispersion of $σ_{\rm obs}=109 \pm 27$ km s$^{-1}$ for the nearer source. Using $σ_{\rm obs}$ for the main deflector (from literature) and S1, we test the robustness of our DSPL model. We measure $β=0.953^{+0.008}_{-0.010}$ for AGEL1507 and infer $Ω_{\rm m}=0.33^{+0.38}_{-0.23}$ for $Λ$CDM cosmology. Combining AGEL1507 with the published model of the Jackpot lens improves the precision on $Ω_{\rm m}$ ($Λ$CDM) and w (wCDM) by $\sim 10 \%$. The inclusion of DSPLs significantly improves the constraints when combined with Plancks cosmic microwave background observations, enhancing precision on w by $30 \%$. This paper demonstrates the constraining power of DSPLs and their complementarity to other standard cosmological probes. Tighter future constraints from larger DSPL samples discovered from ongoing and forthcoming large-area sky surveys would provide insights into the nature of dark energy.
We all love the ecstasy that comes with submitting papers to journals or arXiv. Some have described it as yeeting their back-breaking products of labor into the void, wishing they could never deal with them ever again. The very act of yeeting papers onto arXiv contributes to the expansion of the arXiverse; however, we have yet to quantify our contribution to the cause. In this work, I investigate the expansion of the arXiverse using the arXiv astro-ph submission data from 1992 to date. I coin the term "the arXiverse constant", $a_0$, to quantify the rate of expansion of the arXiverse. I find that astro-ph as a whole has a positive $a_0$, but this does not always hold true for the six subcategories of astro-ph. I then investigate the temporal changes in $a_0$ for the astro-ph subcategories and astro-ph as a whole, from which I infer the fate of the arXiverse.
Urmila Chadayammuri, Lukas Eisert, Annalisa Pillepich
et al.
The physical properties of the intracluster medium (ICM) reflect signatures of the underlying gravitational potential, mergers and strong interactions with other halos and satellite galaxies, as well as galactic feedback from supernovae and supermassive black holes (SMBHs). Traditionally, clusters have been characterized in terms of summary statistics, such as halo mass, X-ray luminosity, cool-core state, luminosity of AGN, and number of merging components. In this paper of the Extracting Reality from Galaxy Observables with Machine Learning series (ERGO-ML), we instead consider the full information content available in maps of X-ray emission from the ICM. We employ Nearest Neighbour Contrastive Learning (NNCLR) to identify and populate a low-dimensional representation space of such images. Using idealized X-ray maps of the 352 clusters of the TNG-Cluster cosmological magnetohydrodynamical simulation suite, we take three orthogonal projections of each cluster at eight snapshots within the redshift range $0\leq z<1$, resulting in a dataset of $\sim$8,000 images. Our findings reveal that this representation space forms a continuous distribution from relaxed to merging objects, and from centrally-peaked to flat emission profiles. The representation also exhibits clear trends with redshift, with halo, gas, stellar, and SMBH mass, with time since a last major merger, and with indicators of dynamical state. We show that an 8-dimensional representation can be used to predict a variety of cluster properties, find analogs, and identify correlations between physical properties, thereby suggesting causal relationships. Our analysis demonstrates that contrastive learning is a powerful tool for characterizing galaxy clusters from their images alone, allowing us to derive constraints on their physical properties and formation histories using cosmological hydrodynamical galaxy simulations.
The current research investigates the behavior of the Tsallis holographic dark energy (THDE) model with quintessence in a homogeneous and anisotropic Bianchi type-III (B-III) space-time. We construct the model by using two conditions (i) expansion scalar (\theta) is proportionate to shear scalar (\sigma) in the model and (ii) hybrid {\color{blue} scale factor} a = t^\beta e^{\gamma t}, where \beta>0, \gamma>0 are constants. Our study is based on Type Ia supernovae (SNIa) data in combination with CMB and BAO observations (Giostri et al, JCAP 3, 27 (2012), arXiv:1203.3213v2[astro-ph.CO]), the present values of Hubble constant and deceleration parameter are H_{0} = 73.8 and q_{0} = -0.54 respectively. Compiling our theoretical models with this data, we obtain \beta = 2.1445~ \& ~ 2.1154 for \gamma = 0.5 ~ \& ~ 1 respectively. We completed an entirely novel form of cosmic model where the expansion occurs during the present accelerated phase for the constraints. We have discussed the conformity among the scalar field model of quintessence and THDE model. To understand the Universe, we have also established the relations for Distance modulus, Luminosity distance, and Angular-diameter distance. Some geometric and physical aspects of the THDE model are also highlighted.
NANOGrav, EPTA, PPTA, and CPTA have announced the evidence for a stochastic signal from their latest data sets. Supermassive black hole binaries (SMBHBs) are supposed to be the most promising gravitational-wave (GW) sources of pulsar timing arrays. Assuming an astro-informed formation model, we use the NANOGrav 15-year data set to constrain the gravitational wave background (GWB) from SMBHBs. Our results prefer a large turn-over eccentricity of the SMBHB orbit when GWs begin to dominate the SMBHBs evolution. Furthermore, the GWB spectrum is extrapolated to the space-borne GW detector frequency band by including inspiral-merge-cutoff phases of SMBHBs and should be detected by LISA, Taiji and TianQin in the near future.
A. Drlica-Wagner, P. S. Ferguson, M. Adamów
et al.
We present the second public data release (DR2) from the DECam Local Volume Exploration survey (DELVE). DELVE DR2 combines new DECam observations with archival DECam data from the Dark Energy Survey, the DECam Legacy Survey, and other DECam community programs. DELVE DR2 consists of ~160,000 exposures that cover >21,000 deg^2 of the high Galactic latitude (|b| > 10 deg) sky in four broadband optical/near-infrared filters (g, r, i, z). DELVE DR2 provides point-source and automatic aperture photometry for ~2.5 billion astronomical sources with a median 5σ point-source depth of g=24.3, r=23.9, i=23.5, and z=22.8 mag. A region of ~17,000 deg^2 has been imaged in all four filters, providing four-band photometric measurements for ~618 million astronomical sources. DELVE DR2 covers more than four times the area of the previous DELVE data release and contains roughly five times as many astronomical objects. DELVE DR2 is publicly available via the NOIRLab Astro Data Lab science platform.
Abstract New series of thermo-pH responsive terpolymers were fabricated. Cationic acrylate tertiary amine monomer based on vanillin was synthesized in two steps and named by [2-((ditert-butylamino)methyl)-4-formyl-6-methoxyphenyl acrylate] and abbreviated as (DTBAVA). 1H NMR, 13C NMR investigated the new compounds, and FT IR exhibited good results. The new terpolymer was fabricated by the free radical polymerization of N-isopropylacrylamide NIPAAm, 10 mol% N, N-dimethylacrylamide and 5, 10, and 20 mol% DTBAVA. The investigation process involved the chemical method such as 1H NMR and FT IR; physical methods for the solid terpolymers as glass temperature by DSC, polymer degradation by TGA, and polymer crystallinity via XRD. For terpolymer solution, gel permeation chromatography GPC was performed for molecular weights and dispersity; contact angles for identifying the hydrophilic or hydrophobic terpolymers solutions. The lower critical solution temperatures Tc,s, and cloud points Cp,s of terpolymers were recorded considering the impact of pH solutions and the concentrations of different sodium salts of (SO4-2, Cl-1, and SCN-1) kosmotropes to chaotropic in the Hofmeister series; turbidity measurements were used via UV/vis spectroscopy and micro-DSC. In a new optimization study, we will use these terpolymers in the post-polymerization with biomolecules such as chitosan, protein, and amino acids via Schiff base.
On the one hand, Andriot and Roupec (Fortsch Phys, 1800105, 2019) proposed an alternative refined de Sitter conjecture, which gives a natural condition on a combination of the first and second derivatives of the scalar potential (Andriot and Roupec 2019). On the other hand, in our previous article (Liu in Eur Phys J Plus 136:901, 2021) , we have found that Palatini Higgs inflation model is in strong tension with the refined de Sitter swampland conjecture (Liu 2021). Therefore, following our previous research, in this article we examine if Higgs inflation model and its two variations: Palatini Higgs inflation and Higgs-Dilaton model (Rubio in Front Astron Space Sci, https://doi.org/10.3389/fspas.2018.00050, 2019) can satisfy the “further refining de Sitter swampland conjecture” or not. Based on observational data (Ade et al., Phys Rev Lett 121:221301, 2018; Akrami et al., Planck 2018 results. X. Constraints on inflation, arXiv:1807.06211 [astro-ph.CO], 2018; Aghanim et al., Planck 2018 results: VI. Cosmological parameters, arXiv:1807.06209 [astro-ph.CO], 2018), we find that these three inflationary models can always satisfy this new swampland conjecture if only we adjust the relevant parameters a, b=1-a\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$b = 1-a$$\end{document} and q. Therefore, if the “further refining de Sitter swampland conjecture” does indeed hold, then the three inflationary models might all be in “landscape”.
The refined de Sitter derivative conjecture provides constraints to potentials that are low energy effective theories of quantum gravity. It can give direct bounds on inflationary scenarios and determine whether the theory is in the Landscape or the Swampland (Cheong et al. in Phys Lett B 789:336–340, 2019). Any inflationary model can be checked by these conditions, and non-minimally coupled scalar field theory is not an exception. We consider the “Palatini Higgs inflation” scenario taking the refined de Sitter derivative conjecture into account. According to the latest cosmological observations from Planck 2018, BICEP2+Keck\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {BICEP2+}Keck$$\end{document} (Ade et al. in Phys Rev Lett 121:221301, 2018; Akrami et al in Planck 2018 results. X. Constraints on inflation, 2018. arXiv:1807.06211 [astro-ph.CO]; Aghanim et al. in Planck 2018 results: VI. Cosmological parameters, 2018. arXiv:1807.06209 [astro-ph.CO]) and the bound of non-minimal coupling parameter ξ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\xi $$\end{document} (Shaposhnikov et al. in arXiv:2001.09088v2; in JCAP 07:064, 2020), we suggest that if the refined dS conjecture does indeed hold, then the Palatini Higgs inflation model cannot be the low energy effective theory of a consistent quantum gravity theory since the two parameters c1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$c_1$$\end{document} and c2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$c_2$$\end{document} are much smaller than order 1, which is inconsistent with the refined dS conjecture. Therefore, we suggest that it is in the “Swampland.”
A. Drlica-Wagner, J. L. Carlin, D. L. Nidever
et al.
The DECam Local Volume Exploration survey (DELVE) is a 126-night survey program on the 4-m Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile. DELVE seeks to understand the characteristics of faint satellite galaxies and other resolved stellar substructures over a range of environments in the Local Volume. DELVE will combine new DECam observations with archival DECam data to cover ~15000 deg$^2$ of high-Galactic-latitude (|b| > 10 deg) southern sky to a 5$σ$ depth of g,r,i,z ~ 23.5 mag. In addition, DELVE will cover a region of ~2200 deg$^2$ around the Magellanic Clouds to a depth of g,r,i ~ 24.5 mag and an area of ~135 deg$^2$ around four Magellanic analogs to a depth of g,i ~ 25.5 mag. Here, we present an overview of the DELVE program and progress to date. We also summarize the first DELVE public data release (DELVE DR1), which provides point-source and automatic aperture photometry for ~520 million astronomical sources covering ~5000 deg$^2$ of the southern sky to a 5$σ$ point-source depth of g=24.3, r=23.9, i=23.3, and z=22.8 mag. DELVE DR1 is publicly available via the NOIRLab Astro Data Lab science platform.
The current research investigates the behavior of the Tsallis holographic dark energy (THDE) model with quintessence in a homogeneous and anisotropic Bianchi type-III (B-III) space-time. We construct the model by using two conditions (i) expansion scalar ($\theta$) is proportionate to shear scalar ($\sigma$) in the model and (ii) hybrid expansion law $a = t^\beta e^{\gamma t}$, where $\beta>0$, $\gamma>0$. Our study is based on Type Ia supernovae (SNIa) data in combination with CMB and BAO observations (Giostri et al, JCAP 3, 27 (2012), arXiv:1203.3213v2[astro-ph.CO]), the present values of Hubble constant and deceleration parameter are $H_{0} = 73.8$ and $q_{0} = -0.54$ respectively. Compiling our theoretical models with this data, we obtain $\beta = 2.1445~ \&~ 2.1154$ for $\gamma = 0.5 ~ \&~ 1$ respectively. We have completed a new type of cosmic model for which the expansion occurs to the current accelerated phase for the restraints. We have discussed the conformity among the scalar field model of quintessence and THDE model. To understand the Universe, we have also established the relations for Distance modulus, Luminosity Distance, and Angular-diameter distance. Some geometric and physical aspects of the THDE model are also highlighted.
Mainly motivated by the recent GW190521 mass gap event which we take as a benchmark point, we critically assess if binaries made of a primordial black hole and a black hole of astrophysical origin may form, merge in stellar clusters and reproduce the LIGO/Virgo detection rate. While two previously studied mechanisms -- the direct capture and the three body induced -- seem to be inefficient, we propose a new "catalysis" channel based on the idea that a subsequent chain of single-binary and binary-binary exchanges may lead to the formation of a high mass binary pairs and show that it may explain the recent GW190521 event if the local overdensity of primordial black holes in the globular cluster is larger than a few.
IceCube Collaboration, M. G. Aartsen, M. Ackermann
et al.
We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010 -- 2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated ($\sim 90 \%$) by electron and tau flavors. The flux, observed in the sensitive energy range from $16\,\mathrm{TeV}$ to $2.6\,\mathrm{PeV}$, is consistent with a single power-law model as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be $γ=2.53\pm0.07$ and a flux normalization for each neutrino flavor of $φ_{astro} = 1.66^{+0.25}_{-0.27}$ at $E_{0} = 100\, \mathrm{TeV}$, in agreement with IceCube's complementary muon neutrino results and with all-neutrino flavor fit results. In the measured energy range we reject spectral indices $γ\leq2.28$ at $\ge3σ$ significance level. Due to high neutrino energy resolution and low atmospheric neutrino backgrounds, this analysis provides the most detailed characterization of the neutrino flux at energies below $\sim100\,{\rm{TeV}}$ compared to previous IceCube results. Results from fits assuming more complex neutrino flux models suggest a flux softening at high energies and a flux hardening at low energies (p-value $\ge 0.06$). The sizable and smooth flux measured below $\sim 100\,{\rm{TeV}}$ remains a puzzle. In order to not violate the isotropic diffuse gamma-ray background as measured by the Fermi-LAT, it suggests the existence of astrophysical neutrino sources characterized by dense environments which are opaque to gamma-rays.
Investigation of quasar emission line properties and relationships between spectral parameters is important for understanding the physical mechanisms that originate inside different regions of the active galactic nuclei. In this paper, we investigate the optical spectral parameters of type 1 quasars taken from the Sloan Digital Sky Survey Data Release 7 Quasar Catalog (arXiv:1006.5178 [astro-ph.CO]). Spectral parameters, such are equivalent widths and full widths at half maximum of both narrow and broad lines are taken into account. We perform the analysis of correlation matrix and principal component analysis of our sample. We obtain that the narrow line Baldwin effect is significant enough and deserves further investigation. We provide the correlation coefficients and slope values for Baldwin effect in several narrow lines.
We show that the model of superfluid dark matter developed in Refs. Khoury (Phys Rev D 91(2):024022, https://doi.org/10.1103/PhysRevD.91.024022, arXiv:1409.0012 [hep-th], 2015), Berezhiani and Khoury (Phys Rev D 92:103510, https://doi.org/10.1103/PhysRevD.92.103510, arXiv:1507.01019 [astro-ph.CO], 2015) and Berezhiani and Khoury (Phys Lett B 753:639, https://doi.org/10.1016/j.physletb.2015.12.054, arXiv:1506.07877 [astro-ph.CO], 2016), which modifies the Newtonian potential and explains the galactic rotational curves, can be unitarized by the formation of classical configurations in the scattering amplitudes. The classicalization mechanism may also trigger the formation of the superfluid state from the early to the late Universe.
In this work, we compare the impacts given by χ 2 statistics and Bayesian statistics. Bayesian statistics is a new statistical method proposed by [C. Ma, P. S. Corasaniti, and B. A. Bassett, arXiv:1603.08519[astro-ph.CO](2016)] recently, which gives a fully account for the standard-candle parameter dependence of the data covariance matrix. For this two statistical methods, we explore the possible redshift-dependence of stretch-luminosity parameter α and color-luminosity parameter β by using redshift tomography. By constraining the ΛCDM model, we check the consistency of cosmology-fit results given by the SN sample of each redshift bin. We also adopt the linear parametrization to explore the possible evolution of α and β and the deceleration parameter q(z) for CPL, JBP, BA and Wang models. We find that: (i) Using the full JLA data, at high redshift α has a trend of decreasing at more than 1.5σ confidence level (CL), and β has a significant trend of decreasing at more than 19σ CL. (ii) Compared with χ 2 statistics (constant α, β) and Bayesian statistics (constant α, β), Bayesian statistics (linear α and β) yields a larger best-fit value of fractional matter density Ω m 0 from JLA+CMB+GC data, which is much closer to slightly deviates from the best-fit result given by other cosmological observations. (iii) The figure of merit (FoM) given by JLA+CMB+GC data from Bayesian statistics is also larger than the FoM from χ 2 statistics, which indicates that former statistics has a better accuracy. (iv) q(z) given by both statistical methods favor an eternal cosmic acceleration at 1σ CL.
The Kilo-Degree Survey (KiDS) is an ongoing optical wide-field imaging survey with the OmegaCAM camera at the VLT Survey Telescope, specifically designed for measuring weak gravitational lensing by galaxies and large-scale structure. When completed it will consist of 1350 square degrees imaged in four filters (ugri). Here we present the fourth public data release which more than doubles the area of sky covered by data release 3. We also include aperture-matched ZYJHKs photometry from our partner VIKING survey on the VISTA telescope in the photometry catalogue. We illustrate the data quality and describe the catalogue content. Two dedicated pipelines are used for the production of the optical data. The Astro-WISE information system is used for the production of co-added images in the four survey bands, while a separate reduction of the r-band images using the theli pipeline is used to provide a source catalogue suitable for the core weak lensing science case. All data have been re-reduced for this data release using the latest versions of the pipelines. The VIKING photometry is obtained as forced photometry on the theli sources, using a re-reduction of the VIKING data that starts from the VISTA pawprints. Modifications to the pipelines with respect to earlier releases are described in detail. The photometry is calibrated to the Gaia DR2 G band using stellar locus regression. In this data release a total of 1006 square-degree survey tiles with stacked ugri images are made available, accompanied by weight maps, masks, and single-band source lists. We also provide a multi-band catalogue based on r-band detections, including homogenized photometry and photometric redshifts, for the whole dataset. Mean limiting magnitudes (5 sigma in a 2" aperture) are 24.23, 25.12, 25.02, 23.68 in ugri, respectively, and the mean r-band seeing is 0.70".
We investigate a new class of LRS Bianchi type-II cosmological models by revisiting in the paper of Mishra {\it et al} (2013) by considering a new deceleration parameter (DP) depending on the time in string cosmology for the modified gravity theory suggested by S$\acute{a}$ez \& Ballester (1986). We have considered the energy-momentum tensor proposed by Leteliar (1983) for bulk viscous and perfect fluid under some assumptions. To make our models consistent with recent astronomical observations, we have used scale factor (Sharma {\it et al} 2018; Garg {\it et al} 2019) $ a(t)=\exp{[\frac{1}β\sqrt{2 βt + k}]}$, where $β$ and $k$ are positive constants and it provides a time-varying DP. By using the recent constraints ($H_{0}=73.8$, and $q_{0} = -0.54$) from SN Ia data in combination with BAO and CMB observations (Giostri {\it et al}, arXiv:1203.3213v2[astro-ph.CO]), we affirm $β= 0.0062$ and $k = 0.000016$. For these constraints, we have substantiated a new class of cosmological transit models for which the expansion takes place from early decelerated phase to the current accelerated phase. Also, we have studied some physical, kinematic and geometric behavior of the models, and have found them consistent with observations and well established theoretical results . We have also compared our present results with those of Mishra {\it et al} (2013) and observed that the results in this paper are much better, stable under perturbation and in good agreement with cosmological reflections.