Search Publications
De-noising the galaxies in the Hubble XDF with EMPCA
Maturi, Matteo
We present a method to model optical images of galaxies using expectation maximization principal components analysis. The method returns de-noised images, it relies on the data alone and does not assume any pre-established model or fitting formula. It preserves the statistical properties of the sample, minimizing possible biases. The precision of …
Hard X-ray spectral investigations of gamma-ray bursts 120521C and 130606A at high-redshift z ∼ 6
Tashiro, M. S.; Urata, Y.; Yasuda, T. +1 more
This study presents a temporal and spectral analysis of the prompt emission of two high-redshift gamma-ray bursts (GRBs), 120521C at z ∼ 6 and 130606A at z ∼ 5.91, using data obtained from the Swift-XRT/BAT and the Suzaku-WAM simultaneously. Based on follow-up XRT observations, the longest durations of the prompt emissions were approximately 80 s …
A Herschel resolved debris disc around HD 105211
Marshall, J. P.; Horner, J.; Marsden, S. C. +1 more
Debris discs are the dusty aftermath of planet formation processes around main-sequence stars. Analysis of these discs is often hampered by the absence of any meaningful constraint on the location and spatial extent of the disc around its host star. Multi-wavelength, resolved imaging ameliorates the degeneracies inherent in the modelling process, …
Probing the cold and warm molecular gas in the Whirlpool Galaxy: Herschel SPIRE-FTS observations of the central region of M51 (NGC 5194)
Cooray, A.; De Looze, I.; Wu, R. +12 more
We present Herschel Spectral and Photometric Imaging Receiver (SPIRE)-Fourier Transform Spectrometer (FTS) intermediate-sampled mapping observations of the central ∼8 kpc (∼150 arcsec) of M51, with a spatial resolution of 40 arcsec. We detect four 12CO transitions (J = 4-3 to J = 7-6) and the [C I] 3P2-3…
Three-dimensional Aquila Rift: magnetized H I arch anchored by molecular complex
Nakanishi, Hiroyuki; Sofue, Yoshiaki
Three-dimensional structure of the Aquila Rift of magnetized neutral gas is investigated by analysing H I and CO line data. The projected distance on the Galactic plane of the H I arch of the Aquila Rift is r⊥ ∼ 250 pc from the Sun. The H I arch emerges at l ∼ 30°, reaches to altitudes as high as ∼500 pc above the plane at l ∼ 350°, and…
An infrared photometric and spectroscopic study of post-AGB stars
Janardhan, P.; Pandey, R.; Anandarao, B. G. +1 more
We present here Spitzer mid-infrared (IR) spectra and modelling of the spectral energy distribution (SED) of a selection of post-asymptotic giant branch (PAGB) stars. The mid-IR spectra of the majority of these sources showed spectral features such as polycyclic aromatic hydrocarbons (PAHs) and silicates in emission. Our results from SED modelling…
High-resolution spectroscopy and abundance analysis of δ Scuti stars near the γ Doradus instability strip
Kambe, E.; Niemczura, E.; Molenda-Żakowicz, J. +5 more
δ Scuti stars are remarkable objects for asteroseismology. In spite of decades of investigations, there are still important questions about these pulsating stars to be answered, such as their positions in log Teff-log g diagram, or the dependence of the pulsation modes on atmospheric parameters and rotation. Therefore, we performed a de…
Investigating the nature of the INTEGRAL gamma-ray bursts and sub-threshold triggers with Swift follow-up
Götz, D.; Mereghetti, S.; Gehrels, N. +9 more
We explore the potential of the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) to improve our understanding of the low-fluence regime for explosive transients, such as Gamma-ray Bursts (GRBs). We probe the nature of the so-called 'WEAK' INTEGRAL triggers, when the gamma-ray instruments record intensity spikes that are below the usual S…
Discussing the distance bias in the estimation of Hi-GAL compact source physical properties - II. Evolutionary status and star formation rate
Elia, D.; Pezzuto, S.; Schisano, E. +2 more
The derivation of the evolutionary stage and rate of star formation of star-forming sites from Galactic single-dish far-infrared and submillimetre surveys suffers from the relatively limited spatial resolution that prevents access to 'core' scales (r ≤ 0.1 pc) for heliocentric distances d ≳ 1 kpc. In a previous article, we studied the implications…
Identifying four INTEGRAL sources in the Galactic plane via VLT/optical and XMM-Newton/X-ray spectroscopy
Rahoui, Farid; Krivonos, Roman; Tomsick, John. A.
We report on FORS2 (FOcal Reducer/low dispersion Spectrograph 2) spectroscopy aiming at the identification of four Galactic plane sources discovered by INTEGRAL, IGR J18088-2741, IGR J18381-0924, IGR J17164-3803, and IGR J19173+0747, complemented by XMM-Newton spectroscopy for IGR J18381-0924. The presence of broad H I and He I emission lines and …