Search Publications
Broad-band X-ray analysis of local mid-infrared-selected Compton-thick AGN candidates
Pozzi, F.; Vignali, C.; Gruppioni, C. +2 more
The estimate of the number and space density of obscured active galactic nuclei (AGNs) over cosmic time still represents an open issue. While the obscured AGN population is a key ingredient of the X-ray background synthesis models and is needed to reproduce its shape, a complete census of obscured AGN is still missing. Here we test the selection o…
A SINFONI view of the nuclear activity and circumnuclear star formation in NGC 4303 - II. Spatially resolved stellar populations
Colina, L.; Burtscher, L.; Pastoriza, M. G. +11 more
We present a spatially resolved stellar population study of the inner ∼200 pc radius of NGC 4303 based on near-infrared integral field spectroscopy with SINFONI/VLT at a spatial resolution of 40-80 pc and using the STARLIGHT code. We found that the distribution of the stellar populations presents a spatial variation, suggesting an age stratificati…
Kinematic signatures of cluster formation from cool collapse in the Lagoon Nebula cluster NGC 6530
Parker, Richard J.; Wright, Nicholas J.
We examine the mass dependence of the velocity dispersion of stars in the young cluster NGC 6530 to better understand how it formed. Using a large sample of members we find that the proper motion velocity dispersion increases with stellar mass. While this trend is the opposite of that predicted if the cluster were developing energy equipartition, …
Hidden IR structures in NGC 40: signpost of an ancient born-again event
Guerrero, M. A.; Toalá, J. A.; Todt, H. +1 more
We present the analysis of infrared (IR) observations of the planetary nebula NGC 40 together with spectral analysis of its [WC]-type central star HD 826. Spitzer IRS observations were used to produce spectral maps centred at polycyclic aromatic hydrocarbons (PAH) bands and ionic transitions to compare their spatial distribution. The ionic lines s…
Bok globule CB 17: polarization, extinction and distance
Medhi, B. J.; Das, H. S.; Choudhury, G. B. +1 more
In this article, the results obtained from a polarimetric study of Bok globule CB 17 in both optical and submillimetre wavelengths are presented. Optical polarimetric observations in the R band (λ = 630 nm, Δλ = 120 nm) were conducted with the 1.04-m Sampurnanand Telescope, Aryabhatta Research Institute of observational sciencES (ARIES), in Nainit…
Merging cold front and AGN feedback in the peculiar galaxy cluster Abell 2626
Pawar, P. K.; Sonkamble, S. S.; Patil, M. K. +1 more
This paper presents the analysis of combined 134 ks Chandra data of a peculiar galaxy cluster Abell 2626. This study confirms the earlier detection of the east cavity at ∼13 kpc and reports the detection of a new cavity at ∼39 kpc to the west of the X-ray peak. The average mechanical power injected by the active galactic nucleus outburst P_cav ∼ 6…
Characterizing dynamical stages of open clusters located in the Sagittarius spiral arm
Maia, F. F. S.; Angelo, M. S.; Dias, W. S. +1 more
The study of dynamical properties of Galactic open clusters (OCs) is a fundamental prerequisite for the comprehension of their dissolution processes. In this work, we characterized 12 OCs, namely: Collinder 258, NGC 6756, Czernik 37, NGC 5381, Ruprecht 111, Ruprecht 102, NGC 6249, Basel 5, Ruprecht 97, Trumpler 25, ESO 129-SC32, and BH 150, projec…
Hunting for brown dwarfs in the globular cluster M4: second epoch HST NIR observations
Knigge, C.; Bedin, L. R.; Rich, R. M. +5 more
We present an analysis of the second epoch Hubble Space TelescopeWide Field Camera 3 F110W near-infrared (NIR) imaging data of the globular cluster M 4. The new data set suggests that one of the previously suggested four brown dwarf candidates in this cluster is indeed a high-probability cluster member. The position of this object in the NIR colou…
Tentative detection of the circumgalactic medium of the isolated low-mass dwarf galaxy WLM
McQuinn, Kristen B. W.; Lockman, Felix J.; Fox, Andrew J. +7 more
We report a tentative detection of the circumgalactic medium (CGM) of Wolf-Lundmark-Melotte (WLM), an isolated, low-mass (logM*/M⊙ ≈ 7.6), dwarf irregular galaxy in the Local Group (LG). We analyse an HST/COS archival spectrum of a quasar sightline (PHL2525), which is 45 kpc (0.5 virial radius) from WLM and close to the Magel…
Co-spatial UV-optical HST/STIS spectra of six planetary nebulae: nebular and stellar properties
Corradi, Romano L. M.; Balick, Bruce; Shaw, Richard A. +4 more
This paper represents the conclusion of a project that had two main goals: (1) to investigate to what extent planetary nebulae (PNe) are chemically homogeneous; and (2) to provide physical constraints on the central star properties of each PN. We accomplished the first goal by using HST/STIS spectra to measure the abundances of seven elements in n…