Search Publications
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…
A combined X-ray, optical, and radio view of the merging galaxy cluster MACS J0417.5-1154
Simionescu, A.; Limousin, M.; Raychaudhury, S. +3 more
We present a comprehensive multiwavelength analysis of the merging galaxy cluster MACS J0417.5-1154 at a redshift of z = 0.44, using available images red obtained with Chandra in X-ray, Subaru, Hubble Space Telescope (HST) in optical, Giant Metrewave Radio Telescope (GMRT) in radio, and Bolocam at 2.1 mm wavelength. This is an example of a complex…
Multiple populations in integrated light spectroscopy of intermediate-age clusters
Salaris, Maurizio; Kamann, Sebastian; Schiavon, Ricardo P. +9 more
The presence of star-to-star light-element abundance variations (also known as multiple populations, MPs) appears to be ubiquitous within old and massive clusters in the Milky Way and all studied nearby galaxies. Most previous studies have focused on resolved images or spectroscopy of individual stars, although there has been significant effort in…
Evolution of X-ray irradiation during the 1999-2000 outburst of the black hole binary XTE J1859 + 226
Done, Chris; Kimura, Mariko
X-ray irradiation in X-ray binaries is thought to control the behaviour at the outer disc, which is observable mainly at optical wavelengths. It is generally parametrized phenomenologically, but it can also be predicted from theoretical models of irradiated discs and their coronae/winds. We test these models using five multiwavelength Hubble Space…