Search Publications
Constraining f(R) gravity with Planck data on galaxy cluster profiles
Atrio-Barandela, F.; De Martino, I.; De Laurentis, M. +1 more
Models of f(R) gravity that introduce corrections to the Newtonian potential in the weak field limit are tested at the scale of galaxy clusters. These models can explain the dynamics of spiral and elliptical galaxies without resorting to dark matter. We compute the pressure profiles of 579 galaxy clusters assuming that the gas is in hydrostatic eq…
Reversal or no reversal: the evolution of the star formation rate-density relation up to z ∼ 1.6
Finoguenov, A.; Berta, S.; Magnelli, B. +27 more
We investigate the evolution of the star formation rate (SFR)-density relation in the Extended Chandra Deep Field South and the Great Observatories Origin Deep Survey fields up to z ∼ 1.6. In addition to the `traditional method', in which the environment is defined according to a statistical measurement of the local galaxy density, we use a `dynam…
Age and metallicity gradients support hierarchical formation for M87
Trujillo, Ignacio; Montes, Mireia; Prieto, M. Almudena +1 more
In order to probe the inside-out formation of the most massive galaxies in the Universe, we have explored the radial (0.1 ≲ R ≲ 8 kpc) variation of the spectral energy distribution of M87 from UV to IR. For this purpose, we have combined high-resolution data in 16 different bands. Our analysis indicate that the age of the stellar population of M87…
X-rays from the redshift 7.1 quasar ULAS J1120+0641.
Page, M. J.; Hewett, P. C.; Warren, S. J. +4 more
We present X-ray imaging and spectroscopy of the redshift z = 7.084 radio-quiet quasar ULAS J112001.48+064124.3 obtained with Chandra and XMM-Newton. The quasar is detected as a point source with both observatories. The Chandra observation provides a precise position, confirming the association of the X-ray source and the quasar, while a sufficien…
Irradiated, colour-temperature-corrected accretion discs in ultraluminous X-ray sources
Done, Chris; Sutton, Andrew D.; Roberts, Timothy P.
Although attempts have been made to constrain the stellar types of optical counterparts to ultraluminous X-ray sources (ULXs), the detection of optical variability instead suggests that they may be dominated by reprocessed emission from X-rays which irradiate the outer accretion disc. Here, we report results from a combined X-ray and optical spect…
The Herschel exploitation of local galaxy Andromeda (HELGA) - V. Strengthening the case for substantial interstellar grain growth
Fritz, J.; De Looze, I.; Baes, M. +7 more
In this paper, we consider the implications of the distributions of dust and metals in the disc of M31. We derive mean radial dust distributions using a dust map created from Herschel images of M31 sampling the entire far-infrared peak. Modified blackbodies are fit to approximately 4000 pixels with a varying, as well as a fixed, dust emissivity in…
Integral field unit spectroscopy of 10 early-type galactic nuclei - I. Principal component analysis Tomography and nuclear activity
Ricci, T. V.; Steiner, J. E.; Menezes, R. B.
Most massive galaxies show emission lines that can be characterized as LINERs. To what extent this emission is related to AGNs or to stellar processes is still an open question. In this paper, we analysed a sample of such galaxies to study the central region in terms of nuclear and circumnuclear emission lines, as well as the stellar component pro…
The debris disc of solar analogue τ Ceti: Herschel observations and dynamical simulations of the proposed multiplanet system
Heras, A. M.; Fridlund, M.; Blommaert, J. A. D. L. +16 more
τ Ceti is a nearby, mature G-type star very similar to our Sun, with a massive Kuiper Belt analogue and possible multiplanet system that has been compared to our Solar system. We present Herschel Space Observatory images of the debris disc, finding the disc is resolved at 70 µm and 160 µm, and marginally resolved at 250 µm. The H…
The AIMSS Project II: dynamical-to-stellar mass ratios across the star cluster-galaxy divide
Forbes, Duncan A.; Romanowsky, Aaron J.; Brodie, Jean P. +5 more
The previously clear division between small galaxies and massive star clusters is now occupied by objects called ultra-compact dwarfs (UCDs) and compact ellipticals (cEs). Here we combine a sample of UCDs and cEs with velocity dispersions from the AIMSS project with literature data to explore their dynamical-to-stellar mass ratios. We confirm that…
The low or retrograde spin of the first extragalactic microquasar: implications for Blandford-Znajek powering of jets
Middleton, Matthew J.; Miller-Jones, James C. A.; Fender, Rob P.
Transitions to high mass accretion rates in black hole X-ray binaries are associated with the ejection of powerful, relativistically moving jets. The mechanism that powers such events is thought to be linked to tapping of the angular momentum (spin) of the black hole, the rate of accretion through the disc or some combination of the two. We can at…