We have modelled the inner surface brightness profiles of 39 alleged 'core' galaxies with the core-Sérsic model, and provide new physical parameters for the largest ever sample of 'core' galaxies fit with this model. When present, additional nuclear components were simultaneously modelled and the typical rms scatter of the fits (out to ∼10 ′′ ) is 0.02 mag arcsec −2 . Model-independent estimates of each core's break radius are shown to agree with those from the core-Sérsic model, and a comparison with the Nuker model is provided. We found an absence of cores in what amounts to 18% of the sample which are reclassified here as Sérsic galaxies with low values of n ( 4) and thus shallow inner profile slopes. In general, galaxies with n < 3 and σ < 183 km s −1 do not have depleted cores. We derive updated relations between core-Sérsic break radii, their associated surface brightness, bulge luminosity, central velocity dispersion, and predicted black hole mass for galaxies with depleted cores. With the possible exception of NGC 584, we confirm that the inner negative logarithmic profile slopes γ are 0.3 for the 'core' galaxies, and 0 > γ > −0.1 for six of these. Finally, the central stellar mass deficits are found to have values typically within a factor of 4 of the expected central black hole mass.

New surface brightness profiles from 26 early-type galaxies with suspected partially depleted cores have been extracted from the full radial extent of Hubble Space Telescope images. We have carefully quantified the radial stellar distributions of the elliptical galaxies using the core-Sérsic model whereas for the lenticular galaxies a core-Sérsic bulge plus an exponential disc model gives the best representation. We additionally caution about the use of excessive multiple Sérsic functions for decomposing galaxies and compare with past fits in the literature. The structural parameters obtained from our fitted models are in general, in good agreement with our initial study using radially limited (R < ∼ 10 ′′ ) profiles, and are used here to update several "central" as well as "global" galaxy scaling relations. We find near-linear relations between the break radius R b and the spheroid luminosity L such that R b ∝ L 1.13±0.13 , and with the supermassive black hole mass. This is internally consistent with the notion that major, dry mergers add the stellar and black hole mass in equal proportion, i.e., M BH ∝ L. In addition, we observe a linear relation R b ∝ R 0.98±0.15 e for the core-Sérsic elliptical galaxies-where R e is the galaxies' effective half light radii-which is collectively consistent with the approximately-linear, bright-end of the curved L − R e relation. Finally, we measure accurate stellar mass deficits M def that are in general 0.5−4 M BH , and we identify two galaxies (NGC 1399, NGC 5061) that, due to their high M def /M BH ratio, may have experienced oscillatory core-passage by a (gravitational radiation)-kicked black hole. The galaxy scaling relations and stellar mass deficits favor core-Sérsic galaxy formation through a few "dry" major merger events involving supermassive black holes such that M def ∝ M 3.70±0.76 BH , for M BH > ∼ 2 × 10 8 M ⊙ .

We have used the full radial extent of images from the Hubble Space Telescope's Advanced Camera for Surveys and Wide Field Planetary Camera 2 to extract surface brightness profiles from a sample of six, local lenticular galaxy candidates. We have modelled these profiles using a core-Sérsic bulge plus an exponential disk model. Our lenticular disk galaxies with bulge magnitudes M V −21.30 mag have central stellar deficits, suggesting that these bulges may have formed from 'dry' merger events involving supermassive black holes while their surrounding disk was subsequently built up, perhaps via cold gas accretion scenarios. The central stellar mass deficits M def are roughly 0.5 to 2 M BH (black hole mass), rather than ∼10 to 20 M BH as claimed from some past studies, which is in accord with core-Sérsic model mass deficit measurements in elliptical galaxies. Furthermore, these bulges have Sérsic indices n ∼ 3, half light radii R e < 2 kpc and masses > 10 11 M ⊙ , and therefore appear to be descendants of the compact galaxies reported at z ∼ 1.5 to 2. Past studies which have searched for these local counterparts by using single-component galaxy models to provide the z ∼ 0 size comparisons have over-looked these dense, compact and massive bulges in today's early-type disk galaxies. This evolutionary scenario not only accounts for what are today generally old bulges-which must be present in z ∼ 1.5 images-residing in what are generally young disks, but it eliminates the uncomfortable suggestion of a factor of 3 to 5 growth in size for the compact, z ∼ 1.5 galaxies that are known to possess infant disks.

We present the first data release of high-resolution ( 0.2 arcsec) 1.5-GHz radio images of 103 nearby galaxies from the Palomar sample, observed with the eMERLIN array, as part of the LeMMINGs survey. This sample includes galaxies which are active (LINER and Seyfert) and quiescent (Hii galaxies and Absorption line galaxies, ALG), which are reclassified based upon revised emission-line diagrams. We detect radio emission 0.2 mJy for 47/103 galaxies (22/34 for LINERS, 4/4 for Seyferts, 16/51 for Hii galaxies and 5/14 for ALGs) with radio sizes typically of 100 pc. We identify the radio core position within the radio structures for 41 sources. Half of the sample shows jetted morphologies. The remaining half shows single radio cores or complex morphologies. LINERs show radio structures more core-brightened than Seyferts. Radio luminosities of the sample range from 10 32 to 10 40 erg s −1 : LINERs and Hii galaxies show the highest and the lowest radio powers respectively, while ALGs and Seyferts have intermediate luminosities.We find that radio core luminosities correlate with black hole (BH) mass down to ∼10 7 M , but a break emerges at lower masses. Using [O III] line luminosity as a proxy for the accretion luminosity, active nuclei and jetted Hii galaxies follow an optical fundamental plane of BH activity, suggesting a common disc-jet relationship. In conclusion, LINER nuclei are the scaled-down version of FR I radio galaxies; Seyferts show less collimated jets; Hii galaxies may host weak active BHs and/or nuclear starforming cores; and recurrent BH activity may account for ALG properties.

It has been widely remarked that compact, massive, elliptical-like galaxies are abundant at high redshifts but exceedingly rare in the Universe today, implying significant evolution such that their sizes at z ∼ 2 ± 0.6 have increased by factors of 3 to 6 to become today's massive elliptical galaxies. These claims have been based on studies which measured the half-light radii of galaxies as though they are all single component systems. Here we identify 21 spheroidal stellar systems within 90 Mpc that have half-light, major-axis radii R e 2 kpc, stellar masses 0.7 × 10 11 < M * /M ⊙ < 1.4 × 10 11 , and Sérsic indices typically around a value of n = 2 to 3. This abundance of compact, massive spheroids in our own backyard -with a number density of 6.9 × 10 −6 Mpc −3 (or 3.5×10 −5 Mpc −3 per unit dex in stellar mass) -and with the same physical properties as the high-redshift galaxies, had been over-looked because they are encased in stellar disks which usually result in galaxy sizes notably larger than 2 kpc. Moreover, this number density is a lower limit because it has not come from a volume-limited sample. The actual density may be closer to 10 −4 , although further work is required to confirm this. We therefore conclude that not all massive 'spheroids' have undergone dramatic structural and size evolution since z ∼ 2 ± 0.6. Given that the bulges of local early-type disk galaxies are known to consist of predominantly old stars which existed at z ∼ 2, it seems likely that some of the observed high redshift spheroids did not increase in size by building (3D) triaxial envelopes as commonly advocated, and that the growth of (2D) disks has also been important over the past 9-11 billion years.