ABSTRACT
Observed mass-to-light ratios (M/L) of metal-rich globular clusters (GCs) disagree with theoretical predictions. This discrepancy is of fundamental importance since stellar population models ...provide the stellar masses that underpin most of extragalactic astronomy, near and far. We have derived radial velocities for 1622 stars located in the centres of 59 Milky Way GCs – 12 of which have no previous kinematic information – using integral-field unit data from the WAGGS project. Using N-body models, we determine dynamical masses and M/LV for the studied clusters. Our sample includes NGC 6528 and NGC 6553, which extend the metallicity range of GCs with measured M/L up to Fe/H ∼ −0.1 dex. We find that metal-rich clusters have M/LV more than two times lower than what is predicted by simple stellar population models. This confirms that the discrepant M/L–Fe/H relation remains a serious concern. We explore how our findings relate to previous observations, and the potential causes for the divergence, which we conclude is most likely due to dynamical effects.
Galaxy and Mass Assembly (GAMA) Sureshkumar, U.; Durkalec, A.; Pollo, A. ...
Astronomy and astrophysics (Berlin),
01/2023, Letnik:
669
Journal Article
Recenzirano
Odprti dostop
Aims.
We investigate how different mid-infrared (mid-IR) properties of galaxies are correlated with the environment in which the galaxies are located. For this purpose, we first study the dependence ...of galaxy clustering on the absolute magnitude at 3.4 μm and redshift. Then, we look into the environmental dependence of mid-IR luminosities and the galaxy properties derived from these luminosities. We also explore how various IR galaxy luminosity selections influence the galaxy clustering measurements.
Methods.
We used a set of
W
1 (3.4 μm) absolute magnitude (
M
W
1
) selected samples from the Galaxy and Mass Assembly (GAMA) survey matched with mid-IR properties from the Wide-field Infrared Survey Explorer (WISE) in the redshift range 0.07 ≤
z
< 0.43. We computed the galaxy two-point correlation function (2pCF) and compared the clustering lengths between subsamples binned in
M
W
1
and in redshift. We also measured the marked correlation function (MCF), in which the galaxies are weighted by marks when measuring clustering statistics, using the luminosities in the WISE
W
1 to
W
4 (3.4 to 22 μm) bands as marks. Additionally, we compared the measurements of MCFs with different estimates of stellar mass and star formation rate (SFR) used as marks. Finally, we checked how different selections applied to the sample affect the clustering measurements.
Results.
We show strong clustering dependence on the
W
1 absolute magnitude: galaxies brighter in the
W
1 band are more strongly clustered than their fainter counterparts. We also observe a lack of significant redshift dependence of clustering in the redshift range 0.07 ≤
z
< 0.43. We show that although the
W
1 and
W
2 bands are direct indicators of stellar mass, a galaxy sample selected based on
W
1 or
W
2 bands does not perfectly show the clustering behaviour of a stellar mass-selected sample. The proxy relation between
W
3 and
W
4 bands and SFR is similar. We also demonstrate the influence of estimation techniques of stellar mass and SFR on the clustering measurements.
ABSTRACT
We present the evolution of the star formation dispersion–stellar mass relation (σSFR–M⋆) in the DEVILS D10 region using new measurements derived using the ProSpect spectral energy ...distribution fitting code. We find that σSFR–M⋆ shows the characteristic ‘U-shape’ at intermediate stellar masses from 0.1 < z < 0.7 for a number of metrics, including using the deconvolved intrinsic dispersion. A physical interpretation of this relation is the combination of stochastic star formation and stellar feedback causing large scatter at low stellar masses and AGN feedback causing asymmetric scatter at high stellar masses. As such, the shape of this distribution and its evolution encodes detailed information about the astrophysical processes affecting star formation, feedback and the lifecycle of galaxies. We find that the stellar mass that the minimum σSFR occurs evolves linearly with redshift, moving to higher stellar masses with increasing lookback time and traces the turnover in the star-forming sequence. This minimum σSFR point is also found to occur at a fixed specific star formation rate (sSFR) at all epochs (sSFR ∼ 10−9.6 Gyr−1). The physical interpretation of this is that there exists a maximum sSFR at which galaxies can internally self-regulate on the tight sequence of star formation. At higher sSFRs, stochastic stellar processes begin to cause galaxies to be pushed both above and below the star-forming sequence leading to increased SFR dispersion. As the Universe evolves, a higher fraction of galaxies will drop below this sSFR threshold, causing the dispersion of the low stellar mass end of the star-forming sequence to decrease with time.
We present the new ProFuse R package, a simultaneous spectral (ultraviolet to far infrared) and spatial structural decomposition tool that produces physical models of galaxies and their components. ...This combines the functionality of the recently released ProFound (for automatic source extraction), ProFit (for extended source profiling) and ProSpect (for stellar population modelling) software packages. The key novelty of ProFuse is that it generates images using a self-consistent model for the star formation and metallicity history of the bulge and disk separately, and uses target images across a range of wavelengths to define the model likelihood and optimise our physical galaxy reconstruction. The first part of the paper explores the ProFuse approach in detail, and compares results to published structural and stellar population properties. The latter part of the paper applies ProFuse to 6,664 z < 0.06 GAMA galaxies. Using re-processed ugriZYJHKs imaging we extract structural and stellar population properties for bulges and disks in parallel. As well as producing true stellar mass based mass-size relationships, we further extend this correlation to explore the third dimensions of age and gas phase metallicity. The disks in particular demonstrate strong co-dependency between mass-size-age in a well defined plane, where at a given disk stellar mass younger disks tend to be larger. These findings are in broad agreement with work at higher redshift suggesting disks that formed earlier are physically smaller.
We present extended point spread function (PSF) models for the Hyper Suprime-Cam Subaru Strategic Program Public Data Release 3 (HSC-SSP PDR3) in all \(\textit{g,r,i,Z}\) and \(\textit{Y}\)-bands. ...Due to its 8.2m primary mirror and long exposure periods, HSC combines deep images with wide-field coverage. Both properties make HSC one of the most suitable observing facilities for low surface brightness (LSB) studies, which are particularly sensitive to the PSF. By applying a median stacking technique of point-like sources with different brightness, we show how to construct the HSC-SSP PDR3 PSF models to an extent of R \(\sim\) 5.6 arcmin. These models are appropriate for the HSC-PDR3 intermediate-state data which do not have applied the final aggressive background subtraction. The intermediate-state data is especially stored for users interested in large extended objects, where our new PSFs provide them with a crucial tool to characterise LSB properties at large angles. We demonstrate that our HSC PSFs behave reasonably in two scenarios. In the first one, we generate 2-D models of a bright star, showing no evidence of residual structures across the five bands. In the second scenario, we recreate the PSF-scattered light on mock images with special consideration of the effect of this additional flux on LSB measurements. We find that, despite the well-behaved nature of the HSC-PDR3 PSFs, there is a non-negligible impact on the faint light present in the mock images. This impact could lead to incorrect LSB measurements if a proper star subtraction is not applied.
Radio jets are present in a diverse sample of AGN. However, the mechanisms of jet powering are not fully understood, and it is yet unclear to what extent they obey mass-invariant scaling relations, ...similar to those found for the triggering and fuelling of X-ray selected AGN. We study the incidence of eROSITA/eFEDS X-ray and LOFAR radio AGN as a function of several stellar mass normalised AGN power indicators. A new sample of radio AGN from the LOFAR-eFEDS survey is defined and we publicly release this catalogue, including host galaxy counterparts from the Legacy Survey DR9, LOFAR radio morphologies and host galaxy properties from the complete, spectroscopic (z<0.4) GAMA09 survey. The fraction of GAMA09 galaxies hosting radio, X-ray and both radio and X-ray AGN are calculated as a function of the specific black hole kinetic (\(\lambda_{\rm Jet}\)) and radiative (\(\lambda_{\rm Edd}\)) power. The incidence of eFEDS X-ray AGN as a function of \(\lambda_{\rm Edd}\) shows the same mass-invariance as found in past studies. Meanwhile, radio AGN, regardless of their morphology, are more likely to be hosted in more massive galaxies, at all \(\lambda_{\rm Jet}\). Across the stellar mass range, the compact radio AGN incidence follows the same power-law distribution, showing that it is not only high mass galaxies that host high power radio AGN and vice versa. On the other hand, the incidence of compact and complex radio AGN is boosted at the highest jet powers, diverging from a simple power-law. Interestingly, this increased incidence cannot be explained by more powerful radio AGN lying in more dense environments which could naturally boost their radio luminosity. Overall, we show that statistical incidence studies are a powerful method to probe disk-jet coupling for different AGN accretion modes, although future work on a more reliable determination of jet power for diverse samples of radio AGN is needed.
In this paper we introduce the software package ProPane, written for the R data analysis language. ProPane combines the full range of wcslib projections with the C++ image manipulation routines ...provided by the CImg library. ProPane offers routines for image warping and combining (including stacking), and various related tasks such as image alignment tweaking and pixel masking. It can stack an effectively unlimited number of target frames using multiple parallel cores, and offers threading for many lower level routines. It has been used for a number of current and upcoming large surveys, and we present a range of its capabilities and features. ProPane is already available under a permissive open-source LGPL-3 license at github.com/asgr/ProPane (DOI: 10.5281/zenodo.10057053).
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