arXiv subjects

M. Cardaci

Publications and source records attributed to M. Cardaci.

5 recordsLinked to original sources

arXiv2020

Chemodynamics of Green Pea galaxies -- I. Outflows and turbulence driving the escape of ionising photons and chemical enrichment

We investigate the ionised gas kinematics, physical properties and chemical abundances of SDSS$J$142947, a Green Pea galaxy at redshift z$\sim$0.17 with strong, double-peak Ly$\alpha$ emission and indirect evidence of Lyman continuum (LyC) leakage. Using high-dispersion spectroscopy, we perform a multi-component analysis of emission-line profiles. Our model consistently fits all lines as a narrow component with intrinsic velocity dispersion $\sigma \sim$40 km s$^{-1}$, and two broader blue-shifted components with $\sigma \sim$90 km s$^{-1}$ and $\sim$250 km s$^{-1}$. We find electron densities and temperatures, ionisation conditions, and direct O/H and N/O abundances for each component. A highly ionised, metal-poor, young and compact starburst dominates narrow emission, showing evidence of hard radiation fields and elevated N/O. The blue-shifted broader components are consistent with highly turbulent, possibly clumpy ionised gas at the base of a strong photoionised outflow, which accounts for $\gtrsim$50% of the integrated emission-line fluxes. The outflow is dense and metal-enriched compared to the HII regions, with expansion velocities larger than those obtained from UV interstellar absorption lines under standard assumptions. Some of these metals may be able to escape, with outflows loading factors comparable to those found in high-$z$ galaxies of similar SFR/Area. Our findings depict a two-stage starburst picture; hard radiation fields from young star clusters illuminate a turbulent and clumpy ISM that has been eroded by SNe feedback. While UV data suggest an extended Ly$\alpha$ halo with high average HI column density, LyC photons could only escape from SDSS$J$142947 through low HI density channels or filaments in the ISM approaching density-bounded conditions, traced by outflowing gas.

astro-ph.GA↗

arXiv2018

Connection between the Circumnuclear Star-Forming Regions and the active nuclei in NGC 1068

In recent years, Circumnuclear Star Forming Regions (CNSFRs) have been studied in different frequencies and telescopes, diverse studies about connection between nuclear activity and star formation in the CNSFRs were doing using optical data, IFS and models. We obtain data of the Seyfert 2 galaxy NGC 1068 at J band between 1.35-1.32$\mu$ using the 8.1m Gemini telescope and GNIRS IFU mode. We found the radial velocity and intensity maps for [FeII]$\lambda$12570, Pa$\beta$ $\lambda$12814 and FeII $\lambda$13201 lines of all the components. The gas emission has a double origin associated with photoionization by young stars or excitation by collisions, we found a high influence of shocks produced by the jet. The intensity of Pa$\beta$ emission show that this component is ionized by a younger cluster or more massive stars. From the analysis of the velocity fields, the data related with the component one of Pa$\beta$ are consistent with the presence of rotation which is displaced from the maximum continuous, our observations may point to the presence of a bar.

astro-ph.GA↗

arXiv2014

High velocity blue-shifted FeII absorption in the dwarf star-forming galaxy PHL293B: Evidence for a wind driven supershell?

X-shooter and ISIS WHT spectra of the starforming galaxy PHL 293B also known as A2228-00 and SDSS J223036.79-000636.9 are presented in this paper. We find broad (FWHM = 1000km/s) and very broad (FWZI = 4000km/s) components in the Balmer lines, narrow absorption components in the Balmer series blueshifted by 800km/s, previously undetected FeII multiplet (42) absorptions also blueshifted by 800km/s, IR CaII triplet stellar absorptions consistent with [Fe/H] < -2.0 and no broad components or blushifted absorptions in the HeI lines. Based on historical records, we found no optical variability at the 5 sigma level of 0.02 mag between 2005 and 2013 and no optical variability at the level of 0.1mag for the past 24 years. The lack of variability rules out transient phenomena like luminous blue variables or SN IIn as the origin of the blue shifted absorptions of HI and FeII. The evidence points to either a young and dense expanding supershell or a stationary cooling wind, in both cases driven by the young cluster wind.

astro-ph.GA↗

arXiv2008

Searches for new physics using dijet events at the LHC

We present a concise review of the plans of the ATLAS and CMS collaborations to search for new physics using dijet events. The inclusive cross section as a function of jet p$_{T}$, the dijet mass distribution and the dijet ratio's CMS techniques are presented together with their potential of discovery with a focus on the integrated luminosities of 10, 100 and 1000 pb$^{-1}$. Analogously, the inclusive jet and angular distribution searches in the dijet channel from ATLAS are presented together with the potential of discovery given in terms of needed integrated luminosity.

hep-ex↗

arXiv2007

An X-ray look at the Seyfert 1 Galaxy Mrk 590: XMM-Newton and Chandra reveal complexity in circumnuclear gas

This paper reports on a partially simultaneous observation of the bright Seyfert 1 Galaxy Mrk590, performed by XMM-Newton and Chandra. The long exposure (~100 ks) allows to investigate with great detail the Fe K complex at 6-7 keV and the presence of soft X-ray spectral features. We have analysed XMM-Newton data from the European Photon Imaging Camera (EPIC) in the 0.5-12 keV band and from the Reflection Grating Spectrometer (RGS) in the 0.35-2.5 keV band, and data from the High Energy Transmission Gratings (HETGs) onboard Chandra. UV and optical data from the Optical Monitor (OM) onboard XMM-Newton are also included in the analysis. The broad band spectrum is well described by an unabsorbed power law and three unresolved Fe~K lines in the 6-7 keV range. The presence of a Compton reflection component and a narrow Fe K line at 6.4 keV is consistent with an origin via torus reflection. The ionised Fe lines at ~6.7 and 7 keV are instead most likely originated by scattering on a warm and ionised gas. The soft X-ray spectrum appears to be almost featureless due to the very bright continuum emission, except for one emission line identified as OVIII Ly alpha detected at ~19 Angstrom by both RGS and Chandra-MEG. The emerging picture consists of an active nucleus seen directly on a "clean" line of sight without intervening material, surrounded by photoionised circumnuclear gas at a high ionisation level. We also study three serendipitous sources in the field of view of Chandra and XMM-Newton. One of these sources may be identified with an ULX of L_{0.3-10 keV}~10^{40} ergs/s.

astro-ph↗