12 pages, 4 figures, 2 tables, submitted to ApJL
Most existing criteria derived from progenitor properties of core-collapse supernovae are not very accurate in predicting explosion outcomes. We present a novel look at identifying the explosion outcome of core-collapse supernovae using a machine learning approach. Informed by a sample of 100 2D axisymmetric supernova simulations evolved with Fornax, we train and evaluate a random forest classifier as an explosion predictor. Furthermore, we examine physics-based feature sets including the compactness parameter, the Ertl condition, and a newly developed set that characterizes the silicon/oxygen interface. With over 1500 supernovae progenitors from 9$-$27 M$_{\odot}$, we additionally train an auto-encoder to extract physics-agnostic features directly from the progenitor density profiles. We find that the density profiles alone contain meaningful information regarding their explodability. Both the silicon/oxygen and auto-encoder features predict explosion outcome with $\approx$90\% accuracy. In anticipation of much larger multi-dimensional simulation sets, we identify future directions in which machine learning applications will be useful beyond explosion outcome prediction.
27 pages, 16 figures, resubmitted to ApJ after incorporating reviewer's comments
High-accuracy black hole (BH) masses require excellent spatial resolution that is only achievable for galaxies within ~100 Mpc using present-day technology. At larger distances, BH masses are often estimated with single-epoch scaling relations for active galactic nuclei. This method requires only luminosity and the velocity dispersion of the broad line region (BLR) to calculate a virial product, and an additional virial factor, $f$, to determine BH mass. The accuracy of these single-epoch masses, however, is unknown, and there are few empirical constraints on the variance of $f$ between objects. We attempt to calibrate single-epoch BH masses using spectropolarimetric measurements of nine megamaser galaxies from which we measure the velocity distribution of the BLR. We do not find strong evidence for a correlation between the virial products used for single-epoch masses and dynamical mass, both for the megamaser sample alone and when combined with dynamical masses from reverberation mapping modeling. Furthermore, we find evidence that the virial parameter $f$ varies between objects, but we do not find strong evidence for a correlation with other observable parameters such as luminosity or broad line width. Although we cannot definitively rule out the existence of any correlation between dynamical mass and virial product, we find tension between allowed $f$ values for masers and those widely used in the literature. We conclude that the single-epoch method requires further investigation if it is to be used successfully to infer BH masses.
24 pages, 21 figures, 5 tables, 3 appendixes;
Euclid's photometric galaxy cluster survey has the potential to be a very competitive cosmological probe. The main cosmological probe with observations of clusters is their number count, within which the halo mass function (HMF) is a key theoretical quantity. We present a new calibration of the analytic HMF, at the level of accuracy and precision required for the uncertainty in this quantity to be subdominant with respect to other sources of uncertainty in recovering cosmological parameters from Euclid cluster counts. Our model is calibrated against a suite of N-body simulations using a Bayesian approach taking into account systematic errors arising from numerical effects in the simulation. First, we test the convergence of HMF predictions from different N-body codes, by using initial conditions generated with different orders of Lagrangian Perturbation theory, and adopting different simulation box sizes and mass resolution. Then, we quantify the effect of using different halo-finder algorithms, and how the resulting differences propagate to the cosmological constraints. In order to trace the violation of universality in the HMF, we also analyse simulations based on initial conditions characterised by scale-free power spectra with different spectral indexes, assuming both Einstein--de Sitter and standard $\Lambda$CDM expansion histories. Based on these results, we construct a fitting function for the HMF that we demonstrate to be sub-percent accurate in reproducing results from 9 different variants of the $\Lambda$CDM model including massive neutrinos cosmologies. The calibration systematic uncertainty is largely sub-dominant with respect to the expected precision of future mass-observation relations; with the only notable exception of the effect due to the halo finder, that could lead to biased cosmological inference.
15 pages, 6 figures. Submitted to A&A. Comments are welcome
25 pages, 18 figures. Submitted for publication in ApJ
20 pages, 8 figures, 3 tables. Submitted to ApJ
33 pages, 16 figures, Accepted to ApJ
7 pages, 4 figures. To be submitted. Comments welcome
29 pages, 22 figures, Accepted to the Astrophysical Journal
21 pages, 9 figures, accepted for publication in ApJ
29 pages, 17 figures. Accepted to appear in The Astronomical Journal
Accepted for publication in MNRAS, 18 pages, 15 figures, 1 table
23 pages, 19 figures, submitted to ApJ
11 pages, 6 (+5) Figures, accepted for publication in A&A
SPIE proceedings, SPIE Astronomical Telescopes + Instrumentation 2022, Montr\'eal, Canada; 20 pages, 13 figures, 2 tables
Submitted to ApJL, comments welcome
Accepted for publication in ApJ
The Astrophysical Journal, 2022, to be published Aug 4, 2022
Accepted for publication in Experimental Astronomy
18 pages, 9 figures, submitted to AAS Journals
5 pages + supplementary material. 2 figures
6 pages, 3 figures, Submitted to SciPost Phys.Proc
Submitted to A&A, favorable referee report received, 11 pages, 8 figures
18 pages, 7 figures, Accepted for publication in MNRAS
14 pages, 11 figures, accepted for publication in MNRAS
14 pages, 14 figures, 1 table
29 pages, 13 figures, published in the Astrophysical Journal
12 pages, 7 figures, To appear in SPIE Proceedings of Astronomical Telescopes + Instrumentation, 2022. arXiv admin note: text overlap with arXiv:2109.13958
11 pages, to appear in SPIE Proceedings of Astronomical Telescopes + Instrumentation, 2022
Submitted to The Astrophysical Journal. Comments welcome
5 figures
21 pages, 24 figures, accepted for publication in ApJ
Submitted, ApJ
13 pages, 5 figures, 1 table
Accepted for publication in ApJ, 23 pages, 3 figures
Accepted for publication in A&A
12 pages, 11 figures, accepted for publication in A&A
Submission to SciPost Phys. Proc. arXiv admin note: text overlap with arXiv:1909.04423
17 pages (incl. 5 of appendix), accepted for publication in ApJ
40 pages
8 pages, 2 figures
11 pages, 15 figures, to be published in A&A
A&A, in press; 11 pages, 7 figures
Accepted for publication in the main journal of MNRAS
17 pages, 3 figures, published on Universe as part of the Special Issue "Nuclear Astrophysics in the Era of High Precision Astronomy"
Accepted for publication in the Journal of Astrophysics and Astronomy for Special Issue on Indian Participation in the SKA. Guest Editors: Abhirup Datta, Nirupam Roy, Preeti Kharb and Tirthankar Roy Choudhury). 31 pages, 8 figures, and 4 tables. Comments are welcome
18 pages, 23 Figures. Submitted to A&A
12 pages + references, 7 figures. Proceedings for SPIE Astronomical Telescopes and Instrumentation 2022. Code at this https URL
Submitted to ApJL. Comments are welcome. Data and code to reproduce our results will be made available at niriss.github.io/sparkler.html
11 pages containing 9 plots
accepted for publication in ApJ
11 pages, 8 figures. Submitted to Phys. Rev. D
13 pages, 6 figures
8 pages, 6 figures, to appear in SPIE Proceeding of Astronomical Telescopes + Instrumentation, 2022
8 pages, 7 figures. Accepted for publication in Astronomy & Astrophysics