Search Publications
Nuclear absorption and emission in the AGN merger NGC 6240 : the hard X-ray view
Nardini, Emanuele
We present the analysis of four NuSTAR observations of the luminous infrared galaxy merger NGC 6240 , hosting a close pair of highly obscured active galactic nuclei (AGNs). Over a period of about 2 yr, the source exhibits hard X-ray variability of the order of 20 per cent, peaking around 20 keV. When the two AGNs are resolved with Chandra , column…
Close-up images of the final Philae landing site on comet 67P/Churyumov-Gerasimenko acquired by the ROLIS camera
Bibring, J. -P.; Jaumann, R.; Keller, H. U. +11 more
After coming to rest on the night side of comet 67P/Churyumov-Gerasimenko, the ROLIS camera on-board Rosetta's Philae lander acquired five images of the surface below the lander, four of which were with the aid of LED illumination of different colors. The images confirm that Philae was perched on a sloped surface. A local horizon is visible in one…
Understanding the environment around the intermediate mass black hole candidate ESO 243-49 HLX-1
Maccarone, T. J.; Graham, Alister W.; Combes, F. +12 more
Aims: ESO 243-49 HLX-1, otherwise known as HLX-1, is an intermediate mass black hole (IMBH) candidate located 8'' (3.7 Kpc) from the centre of the edge-on S0 galaxy ESO 243-49. How the black hole came to be associated with this galaxy, and the nature of the environment in which it resides, remain unclear. Using multi-wavelength observations w…
Growth of Bulges in Disk Galaxies Since z ∼ 1
Sachdeva, Sonali; Saha, Kanak; Singh, Harinder P.
We investigate the growth of bulges in bright ({M}B< -20) disk galaxies since z∼ 1, in rest-frame B and I-band, using images from HST ACS and WFC3 in GOODS-South for high redshifts (0.4< z< 1.0) and SDSS for local (0.02< z< 0.05). The growth history has been traced by performing two-component bulge-disk decomposition and …
The effect of stellar and AGN feedback on the low-redshift Lyman α forest in the Sherwood simulation suite
Viel, Matteo; Sijacki, Debora; Kim, Tae-Sun +4 more
We study the effect of different feedback prescriptions on the properties of the low-redshift (z ≤ 1.6) Lyα forest using a selection of hydrodynamical simulations drawn from the Sherwood simulation suite. The simulations incorporate stellar feedback, active galactic nuclei (AGN) feedback and a simplified scheme for efficiently modelling the low co…
Molecular Outflows: Explosive versus Protostellar
Palau, Aina; Zapata, Luis A.; Rodríguez, Luis F. +2 more
With the recent recognition of a second, distinctive class of molecular outflows, namely the explosive ones not directly connected to the accretion-ejection process in star formation, a juxtaposition of the morphological and kinematic properties of both classes is warranted. By applying the same method used in Zapata et al., and using 12
Variation in Coronal Activity from Solar Cycle 24 Minimum to Maximum Using Three-Dimensional Reconstructions of the Coronal Electron Density from STEREO/COR1
Thompson, William T.; Davila, Joseph M.; Wang, Tongjiang +2 more
Three-dimensional electron density distributions in the solar corona are reconstructed for 100 Carrington rotations (CR 2054 - 2153) during 2007/03 - 2014/08 using the spherically symmetric method from polarized white-light observations with the inner coronagraph (COR1) onboard the twin Solar Terrestrial Relations Observatory (STEREO). These three…
ALMA high spatial resolution observations of the dense molecular region of NGC 6302
Sánchez Contreras, C.; Alcolea, J.; Corradi, R. L. M. +5 more
Context. The mechanism behind the shaping of bipolar planetary nebulae is still poorly understood. It is becoming increasingly clear that the main agents must operate at their innermost regions, where a significant equatorial density enhancement should be present and related to the collimation of light and jet launching from the central star prefe…
A comparison between the soft X-ray and [O III] morphologies of active galactic nuclei
Gallego, Jesús; Gómez-Guijarro, Carlos; Rodríguez-Espinosa, José Miguel +2 more
Several studies of nearby active galactic nuclei (AGNs) have shown that the soft X-ray emission presents a size and morphology resembling that of the narrow-line region (NLR) traced by [O III]. Since the NLR is mainly constituted by gas photoionized by the AGN, it seems logical to assume that this is also the primary source of the soft X-ray emiss…
The Proper Motion of Pyxis: The First Use of Adaptive Optics in Tandem with HST on a Faint Halo Object
Neichel, B.; Linden, S. T.; Davies, R. +13 more
We present a proper motion measurement for the halo globular cluster Pyxis, using Hubble Space Telescope/ACS data as the first epoch and GeMS/GSAOI Adaptive Optics data as the second, separated by a baseline of ∼5 years. This is both the first measurement of the proper motion of Pyxis and the first calibration and use of Multi-Conjugate Adaptive O…