11(month)

The Birth of a Relativistic Jet Following the Disruption of a Star by a Cosmological Black Hole

First author: Dheeraj R. Pasham A black hole can launch a powerful relativistic jet after it tidally disrupts a star. If this jet fortuitously aligns with our line of sight, the overall brightness is Doppler boosted by several orders of magnitude. Consequently, such on-axis relativistic tidal disruption events (TDEs) have the potential to unveil cosmological (redshift $z>$1) quiescent black holes and are ideal test beds to understand the radiative mechanisms operating in super-Eddington jets.

The Dark Energy Survey Year 3 high redshift sample: Selection, characterization and analysis of galaxy clustering

First author: C. Sánchez The fiducial cosmological analyses of imaging galaxy surveys like the Dark Energy Survey (DES) typically probe the Universe at redshifts $z < 1$. This is mainly because of the limited depth of these surveys, and also because such analyses rely heavily on galaxy lensing, which is more efficient at low redshifts. In this work we present the selection and characterization of high-redshift galaxy samples using DES Year 3 data, and the analysis of their galaxy clustering measurements.

The volumetric star formation law in nearby galaxies

First author: C. Bacchini Star formation laws are empirical relations between the cold gas (HI+H$_2$) content of a galaxy and its star formation rate (SFR), being crucial for any model of galaxy formation and evolution. A well known example of such laws is the Schmidt-Kennicutt law, which is based on the projected surface densities. However, it has been long unclear whether a more fundamental relation exists between the intrinsic volume densities.

Toward Accurate Modeling of Galaxy Clustering on Small Scales: Halo Model Extensions & Lingering Tension

First author: Gillian D. Beltz-Mohrmann This paper represents an effort to provide robust constraints on cosmology and the galaxy-halo connection using a fully numerical model of small-scale galaxy clustering. We explore two extensions to the standard Halo Occupation Distribution model: assembly bias, whereby halo occupation depends on both halo mass and the larger environment, and velocity bias, whereby galaxy velocities do not perfectly trace the velocity of the dark matter within the halo.

VERTICO III: The Kennicutt-Schmidt relation in Virgo cluster galaxies

First author: M. J. Jiménez-Donaire In this VERTICO science paper we aim to study how the star formation process depends on galactic environment and gravitational interactions in the context of galaxy evolution. We explore the scaling relation between the star formation rate (SFR) surface density and the molecular gas surface density, also known as the Kennicutt-Schmidt (KS) relation, in a subsample of Virgo cluster spiral galaxies. We use new ACA and TP observations from the VERTICO-ALMA Large Program at 720pc resolution to resolve the molecular gas content, as traced by the 12CO(2-1) transition, across the disks of 37 spiral galaxies in the Virgo cluster.

Association of Optical, Ultraviolet and Soft X-ray excess Emissions in AGNs

First author: D. Nour Soft X-ray emission (0.5–2.0 keV) plays a pivotal role in regulating the optical and UV emission in the AGNs. We collected a sample of 1811 AGNs from the SDSS database and obtained various parameters of Balmer lines, optical continuum, MgII line & UV continuum and studied their dependencies on soft X-ray luminosity. Based on the linear regression analysis, we found that FWHM${\text{MgII}}$ $\propto$ FWHM${\text{H}\beta}^{0.554}$ suggesting that UV emission is arising from a region relatively outside the broad line region (BLR) associated to the H$\beta$ emission and found a strong correlation between optical and UV luminosities (L${\text{MgII}}$ $\propto$ L${\text{H}\beta}^{0.

Chemical abundances in the dwarf galaxy NGC 4163 based on the nebular and auroral emission lines

First author: I. A. Zinchenko We constructed an oxygen abundance map and N/O ratio map of the unusually low excitation dwarf irregular galaxy NGC 4163 based on publicly available spectroscopy obtained by the MaNGA survey. We detected auroral emission line [OII]$\lambda\lambda$7320,7330 which allows us to measure chemical abundance by direct T$_e$ method. We found that the scatter of the oxygen abundance derived by the strong line method is large. The oxygen abundances 12 + log(O/H) derived by strong line method vary from ~7.

De-noising non-Gaussian fields in cosmology with normalizing flows

First author: Adam Rouhiainen Fields in cosmology, such as the matter distribution, are observed by experiments up to experimental noise. The first step in cosmological data analysis is usually to de-noise the observed field using an analytic or simulation driven prior. On large enough scales, such fields are Gaussian, and the de-noising step is known as Wiener filtering. However, on smaller scales probed by upcoming experiments, a Gaussian prior is substantially sub-optimal because the true field distribution is very non-Gaussian.

Formation of star clusters and enrichment by massive stars in simulations of low-metallicity galaxies with a fully sampled initial stellar mass function

First author: Natalia Lahén We present new GRIFFIN project hydrodynamical simulations that model the formation of galactic star cluster populations in low-metallicity ($Z=0.00021$) dwarf galaxies, including radiation, supernova and stellar wind feedback of individual massive stars. In the simulations, stars are sampled from the stellar initial mass function (IMF) down to the hydrogen burning limit of 0.08 M$_\odot$. Mass conservation is enforced within a radius of 1 pc for the formation massive stars.

Hard X-ray Observations of the Hydrogen-poor Superluminous Supernova SN 2018hti with NuSTAR

First author: Igor Andreoni Some Hydrogen-poor superluminous supernovae are likely powered by a magnetar central engine, making their luminosity larger than common supernovae. Although a significant amount of X-ray flux is expected from the spin down of the magnetar, direct observational evidence is still to be found, giving rise to the “missing energy” problem. Here we present NuSTAR observations of nearby SN 2018hti 2.4y (rest frame) after its optical peak.