Search Publications
Infrared observations of the flaring maser source G358.93-0.03. SOFIA confirms an accretion burst from a massive young stellar object
Menten, K. M.; Eislöffel, J.; Klose, S. +24 more
Context. Class II methanol masers are signposts of massive young stellar objects (MYSOs). Recent evidence shows that flares of these masers are driven by MYSO accretion bursts. Thus, maser monitoring can be used to identify such bursts which are hard to discover otherwise. Infrared observations reveal burst-induced changes in the spectral energy d…
The properties of polycyclic aromatic hydrocarbons in galaxies: constraints on PAH sizes, charge and radiation fields
Rigopoulou, D.; Pereira-Santaella, M.; Alonso-Herrero, A. +7 more
Based on theoretical spectra computed using Density Functional Theory we study the properties of polycyclic aromatic hydrocarbons (PAH). In particular using bin-average spectra of PAH molecules with varying number of carbons we investigate how the intensity of the mid-infrared emission bands, 3.3, 6.2, 7.7, and 11.3 $\mu$m, respond to changes in t…
Physics of ULIRGs with MUSE and ALMA: The PUMA project. II. Are local ULIRGs powered by AGN? The subkiloparsec view of the 220 GHz continuum
Rigopoulou, D.; Colina, L.; van der Werf, P. +11 more
We analyze new high-resolution (400 pc) ∼220 GHz continuum and CO(2-1) Atacama Large Millimeter Array (ALMA) observations of a representative sample of 23 local (z < 0.165) ultra-luminous infrared systems (ULIRGs; 34 individual nuclei) as part of the "Physics of ULIRGs with MUSE and ALMA" (PUMA) project. The deconvolved half-light radii of the …
Dust/ice mixing in cold regions and solid-state water in the diffuse interstellar medium
Henning, Thomas; Bouwman, Jeroen; Jäger, Cornelia +1 more
Whether ice in cold cosmic environments is physically separated from the silicate dust or mixed with individual silicate moieties is not known. However, different grain models give very different compositions and temperatures of grains. The aim of the present study is to compare the mid-infrared spectra of laboratory silicate grain/water ice mixtu…
A Study of the Photometric and Spectroscopic Variations of the Prototypical FU Orionis-type Star V1057 Cyg
Cseh, B.; Kriskovics, L.; Pál, A. +19 more
Among the low-mass pre-main sequence stars, a small group called FU Orionis-type objects (FUors) are notable for undergoing powerful accretion outbursts. V1057 Cyg, a classical example of an FUor, went into outburst around 1969-1970, after which it faded rapidly, making it the fastest-fading FUor known. Around 1995, a more rapid increase in fading…
X-ray binary accretion states in active galactic nuclei? Sensing the accretion disc of supermassive black holes with mid-infrared nebular lines
Fernández-Ontiveros, Juan A.; Muñoz-Darias, Teo
Accretion states, which are universally observed in stellar mass black holes in X-ray binaries, might be expected in active galactic nuclei (AGN). This is the case at low luminosities, when the jet-corona coupling dominates the energy output in both populations. Previous attempts to extend this framework to a wider AGN population have been extreme…
M17 MIR: A Massive Protostar with Multiple Accretion Outbursts
Chen, Zhiwei; Chen, Xuepeng; Haas, Martin +3 more
We report the discovery of a massive protostar M17 MIR embedded in a hot molecular core in M17. The multiwavelength data obtained during 1993-2019 show significant mid-IR (MIR) variations, which can be split into three stages: the decreasing phase during 1993.03-mid-2004, the quiescent phase from mid-2004 to mid-2010, and the rebrightening phase f…
Tracing PAH Size in Prominent Nearby Mid-Infrared Environments
Tielens, A. G. G. M.; Peeters, E.; Vacca, W. D. +2 more
We present observations from the First Light Infrared TEst CAMera (FLITECAM) on board the Stratospheric Observatory for Infrared Astronomy, the Spitzer Infrared Array Camera (IRAC), and the Spitzer Infrared Spectrograph SH mode in three well-known photodissociation regions, the reflection nebulae (RNe) NGC 7023 and NGC 2023 and to the southeast of…
The 6.2 µm PAH Feature and the Role of Nitrogen: Revisited
Boersma, C.; Peeters, E.; Ricca, A.
This study revisits the role that nitrogen inclusion in polycyclic aromatic hydrocarbons (PAHs; those with nitrogen inclusion, PANHs) plays in their infrared (IR) spectral properties. We present spectra of pure PAHs, PANHs, and protonated PANHs, computed using density functional theory and basis sets that treat polarization. We investigate trends …
The dust mass in Cassiopeia A from infrared and optical line flux differences
De Looze, I.; Barlow, M. J.; Milisavljevic, D. +2 more
The large quantities of dust that have been found in a number of high-redshift galaxies have led to suggestions that core-collapse supernovae (CCSNe) are the main sources of their dust and have motivated the measurement of the dust masses formed by local CCSNe. For Cassiopeia A (Cas A), an oxygen-rich remnant of a Type IIb CCSN, a dust mass of 0.6…