DustKING - the story continues: dust attenuation in NGC628

Dust attenuation is a crucial but highly uncertain parameter that hampers the determination of intrinsic galaxy properties, such as stellar masses, star formation rates and star formation histories. The shape of the dust attenuation law is not expected to be uniform between galaxies, nor within a galaxy. Our DustKING project was introduced at the first BINA workshop in 2016 and aims to study the variations of dust attenuation curves in nearby galaxies. At the second BINA workshop in 2018, I presented the results of our pilot study for the spiral galaxy NGC628. We find that the average attenuation law of this galaxy is characterised by a MW-like bump and a steep UV slope. Furthermore, we observe intriguing variations within the galaxy, with regions of high $A_V$ exhibiting a shallower attenuation curve. Finally, we discuss how our work might benefit from data taken with the UVIT from the Indian AstroSat mission.Comment: 8 pages, 6 figures, Proceedings paper of the second Belgo-Indian Network for Astronomy & astrophysics (BINA) workshop, accepted for publication in the Bulletin de la Soci\'et\'e Royale des Sciences de Li\`eg

DustKING, the story continues : dust attenuation in NGC 628

Dust attenuation is a crucial but highly uncertain parameter that hampers the determination of in- trinsic galaxy properties, such as stellar masses, star formation rates and star formation histories. The shape of the dust attenuation law is not expected to be uniform between galaxies, nor within a galaxy. Our DustKING project was introduced at the first BINA workshop in 2016 and aims to study the variations of dust attenuation curves in nearby galaxies. At the second BINA workshop in 2018, I presented the results of our pilot study for the spiral galaxy NGC 628. We find that the average attenuation law of this galaxy is characterised by a MW-like bump and a steep UV slope. Furthermore, we observe intriguing variations within the galaxy, with regions of high AV exhibiting a shallower attenuation curve. Finally, we discuss how our work might benefit from data taken with the UVIT from the Indian AstroSat mission

The recent star formation history of NGC 628 on resolved scales

Star formation histories (SFHs) are integral to our understanding of galaxy evolution. We can study recent SFHs by comparing the star formation rate (SFR) calculated using different tracers, as each probes a different timescale. We aim to calibrate a proxy for the present-day rate of change in SFR, dSFR/dt, which does not require full spectral energy distribution (SED) modeling and depends on as few observables as possible, to guarantee its broad applicability. To achieve this, we create a set of models in CIGALE and define a SFR change diagnostic as the ratio of the SFR averaged over the past 5 and 200 Myr, ⟨SFR5⟩/⟨SFR200⟩⁠, probed by the Hα −FUV colour. We apply ⟨SFR5⟩/⟨SFR200⟩ to the nearby spiral NGC 628 and find that its star formation activity has overall been declining in the recent past, with the spiral arms, however, maintaining a higher level of activity. The impact of the spiral arm structure is observed to be stronger on ⟨SFR5⟩/⟨SFR200⟩ than on the star formation efficiency (SFEH2⁠). In addition, increasing disk pressure tends to increase recent star formation, and consequently ⟨SFR5⟩/⟨SFR200⟩⁠. We conclude that ⟨SFR5⟩/⟨SFR200⟩ is sensitive to the molecular gas content, spiral arm structure, and disk pressure. The ⟨SFR5⟩/⟨SFR200⟩ indicator is general and can be used to reconstruct the recent SFH of any star-forming galaxy for which Hα, FUV, and either mid- or far-IR photometry is available, without the need of detailed modeling

The distribution of interstellar dust in CALIFA edge-on galaxies via oligochromatic radiative transfer fitting

We investigate the amount and spatial distribution of interstellar dust in edge-on spiral galaxies, using detailed radiative transfer modeling of a homogeneous sample of 12 galaxies selected from the CALIFA survey. Our automated fitting routine, FitSKIRT, was first validated against artificial data. This is done by simultaneously reproducing the SDSS $g$-, $r$-, $i$- and $z$-band observations of a toy model in order to combine the information present in the different bands. We show that this combined, oligochromatic fitting, has clear advantages over standard monochromatic fitting especially regarding constraints on the dust properties. We model all galaxies in our sample using a three-component model, consisting of a double exponential disc to describe the stellar and dust discs and using a S\'ersic profile to describe the central bulge. The full model contains 19 free parameters, and we are able to constrain all these parameters to a satisfactory level of accuracy without human intervention or strong boundary conditions. Apart from two galaxies, the entire sample can be accurately reproduced by our model. We find that the dust disc is about 75% more extended but only half as high as the stellar disc. The average face-on optical depth in the V-band is $0.76$ and the spread of $0.60$ within our sample is quite substantial, which indicates that some spiral galaxies are relatively opaque even when seen face-on.Comment: 18 pages, 6 figures, 4 tables, Accepted for publication in MNRA

The dust mass in Cassiopeia A from infrared and optical line flux differences

The large quantities of dust that have been found in a number of high redshift galaxies have led to suggestions that core-collapse supernovae (CCSNe) are the main sources of their dust and have motivated the measurement of the dust masses formed by local CCSNe. For Cassiopeia~A, an oxygen-rich remnant of a Type~IIb CCSN, a dust mass of 0.6-1.1~M$_\odot$ has already been determined by two different methods, namely (a) from its far-infrared spectral energy distribution and (b) from analysis of the red-blue emission line asymmetries in its integrated optical spectrum. We present a third, independent, method for determining the mass of dust contained within Cas~A. This compares the relative fluxes measured in similar apertures from [O~{\sc iii}] far-infrared and visual-region emission lines, taking into account foreground dust extinction, in order to determine internal dust optical depths, from which corresponding dust masses can be obtained. Using this method we determine a dust mass within Cas~A of at least 0.99$^{+0.10}_{-0.09}$~M$_\odot$.Comment: Accepted by MNRAS, 17 pages, 12 figures. Author accepted manuscript. Accepted on 21/03/2021. Deposited on 22/03/202

Dust survival rates in clumps passing through the Cas A reverse shock -- II. The impact of magnetic fields

Dust grains form in the clumpy ejecta of core-collapse supernovae where they are subject to the reverse shock, which is able to disrupt the clumps and destroy the grains. Important dust destruction processes include thermal and kinetic sputtering as well as fragmentation and grain vaporization. In the present study, we focus on the effect of magnetic fields on the destruction processes. We have performed magneto-hydrodynamical simulations using AstroBEAR to model a shock wave interacting with an ejecta clump. The dust transport and destruction fractions are computed using our post-processing code Paperboats in which the acceleration of grains due to the magnetic field and a procedure that allows partial grain vaporization have been newly implemented. For the oxygen-rich supernova remnant Cassiopeia A we found a significantly lower dust survival rate when magnetic fields are aligned perpendicular to the shock direction compared to the non-magnetic case. For a parallel field alignment, the destruction is also enhanced but at a lower level. The survival fractions depend sensitively on the gas density contrast between the clump and the ambient medium and on the grain sizes. For a low-density contrast of $100$, e.g., $5\,$nm silicate grains are completely destroyed while the survival fraction of $1\,\mu$m grains is $86\,$per cent. For a high-density contrast of $1000$, $95\,$per cent of the $5\,$nm grains survive while the survival fraction of $1\,\mu$m grains is $26\,$per cent. Alternative clump sizes or dust materials (carbon) have non-negligible effects on the survival rate but have a lower impact compared to density contrast, magnetic field strength, and grain size.Comment: Accepted by MNRAS. Author accepted manuscript. Accepted on 23/01/2023. 24 pages, 21 Figure

An extremely low gas-to-dust ratio in the dust-lane lenticular galaxy NGC 5485

Date of Acceptance: 21/07/2014Peer reviewe

High-resolution radiative transfer modelling of M33

The authors thank the anonymous reviewer, whose comments have certainly improved the manuscript. The authors also thank Peter Camps for valuable technical advice, along with all of the participants at the recent SKIRT meeting for comments and discussions. I.D.L. gratefully acknowledges the supports of the Research Foundation – Flanders (FWO). M.W.L.S acknowledges funding from the UK Science and Technology Facilities Council consolidated grant ST/K000926/1. M.R. acknowledges support by the research projects AYA2014-53506-P and AYA2017-84897P from the Spanish Ministerio de Econom´ıa y Competitividad. This research made use of MONTAGE (http://montage.ipac.caltech.edu/), which is funded by the National Science Foundation under Grant Number ACI-1440620, and was previously funded by the National Aeronautics and Space Administration’s Earth Science Technology Office, Computation Technologies Project, under Cooperative Agreement Number NCC5-626 between NASA and the California Institute of Technology. This research has made use of Astropy, a community-developed core PYTHON package for Astronomy (http: //www.astropy.org/; Astropy Collaboration et al. 2013, 2018). This research has made use of NumPy (http://www.numpy.org/; van der Walt, Colbert & Varoquaux 2011), SciPy (http://www.scipy.org/), andMatPlotLib (http://matplotlib.org/; Hunter 2007). This research made use of APLpy, an open-source plotting package for PYTHON (https://aplpy.github.io/; Robitaille & Bressert 2012).In this work, we characterize the contributions from both ongoing star formation and the ambient radiation field in Local Group galaxy M33, as well as estimate the scale of the local dust-energy balance (i.e. the scale at which the dust is re-emitting starlight generated in that same region) in this galaxy through high-resolution radiative transfer (RT) modelling, with defined stellar and dust geometries. We have characterized the spectral energy distribution (SED) of M33 from UV to sub-mm wavelengths, at a spatial scale of 100 pc. We constructed input maps of the various stellar and dust geometries for use in the RTmodelling. By modifying our dust mix (fewer very small carbon grains and a lower silicate-to-carbon ratio as compared to the Milky Way), we can much better fit the sub-mm dust continuum. Using this new dust composition, we find that we are able to well reproduce the observed SED of M33 using our adopted model. In terms of stellar attenuation by dust, we find a reasonably strong, broad UV bump, as well as significant systematic differences in the amount of dust attenuation when compared to standard SED modelling.We also find discrepancies in the residuals of the spiral arms versus the diffuse interstellar medium (ISM), indicating a difference in properties between these two regimes. The dust emission is dominated by heating due to the young stellar populations at all wavelengths (∼80 per cent at 10 μm to ∼50 per cent at 1 mm). We find that the local dust-energy balance is restored at spatial scales greater than around 1.5 kpc.Funding from the UK Science and Technology Facilities Council consolidated grant ST/K000926/1. M.R. acknowledges support by the research projects AYA2014-53506-P and AYA2017-84897P from the Spanish Ministerio de Economía y Competitividad. This research made use of MONTAGE (http://montage.ipac.caltech.edu/), which is funded by the National Science Foundation under Grant Number ACI-1440620, and was previously funded by the National Aeronautics and Space Administration’s Earth Science Technology Office, Computation Technologies Project, under Cooperative Agreement Number NCC5-626 between NASA and the California Institute of Technolog

The origin of [C II] 157 μm emission in a five-component interstellar medium : the case of NGC 3184 and NGC 628

With its relatively low ionization potential, C+ can be found throughout the interstellar medium (ISM) and provides one of the main cooling channels of the ISM via the [C II] 157 mu m emission. While the strength of the [C II] line correlates with the star formation rate, the contributions of the various gas phases to the [C II] emission on galactic scales are not well established. In this study we establish an empirical multi-component model of the ISM, including dense H II regions, dense photon dissociation regions (PDRs), the warm ionized medium (WIM), low density and G(0). surfaces of molecular clouds (SfMCs), and the cold neutral medium (CNM). We test our model on ten luminous regions within the two nearby galaxies NGC 3184 and NGC 628. on angular scales of 500-600 pc. Both galaxies are part of the Herschel. key program. KINGFISH,. and are complemented by a large set of ancillary ground-and space-based data. The five modeled phases together reproduce the observed [C II] emission quite well, overpredicting the total flux slightly (about 45%) averaged over all regions. We find that dense PDRs are the dominating component, contributing 68% of the [C II] flux on average, followed by the WIM and the SfMCs, with mean contributions of about half of the contribution from dense PDRs, each. CNM and dense H II regions are only minor contributors with less than 5% each. These estimates are averaged over the selected regions, but the relative contributions of the various phases to the [C II] flux vary significantly between these regions