Evidence for the absorption of crystalline silicates at 11.1 $\mu$m in the spectra of the nucleus of the Circinus galaxy

2019 ◽  
Vol 488 (1) ◽  
pp. L75-L79
Author(s):  
Tho Do Duy ◽  
Warrick A Lawson
Keyword(s):  
Grain Size ◽  
Milky Way ◽  
Young Stellar Objects ◽  
Line Of Sight ◽  
Stellar Objects ◽  
Mid Infrared ◽  
Profile Shape ◽  
The Earth ◽  
Star Formation Regions ◽  
Galaxy Nucleus

Abstract Several mid-infrared spectra of the Circinus galaxy nucleus taken with T-ReCS on Gemini South and MIDI on VLTI have consistently shown an inflection centred around 11 $\mu$m. We ascribe this feature to the absorption of crystalline silicate, based on their similarity in profile shape and improvement in fitting quality using a partially crystalline silicate model, compared to entirely amorphous models. Spectral fits reveal a fraction of 0.6–2.0 per cent of crystalline forsterite in the nucleus of the Circinus galaxy, which is similar to the values obtained for the interstellar medium (ISM) of the Milky Way. This is probably the first detection of crystalline silicate absorption in the nucleus of this Seyfert 2 galaxy. In addition, the presence of large grain-size amorphous silicates, together with the similarity in profile shape of the optical depth of Circinus with those of young stellar objects in the Milky Way, implies that most of the contribution to the spectra of Circinus comes from dust in the star formation regions near the centre of the nucleus or along the line of sight to the Earth, rather than in the ISM of Circinus. We also compare our optical depths of Circinus with those in previous studies.

scholarly journals Unveiling the Unseen: The Mid-IR Galactic Disk

2009 ◽  
Vol 5 (H15) ◽  
pp. 787-787
Author(s):  
Ed Churchwell
Keyword(s):  
Galactic Disk ◽  
Young Stellar Objects ◽  
Physical Processes ◽  
Stellar Objects ◽  
Mid Infrared ◽  
Dark Clouds ◽  
The Galaxy ◽  
Polycyclic Aromatic ◽  
Star Formation Regions ◽  
Infrared Dark Clouds

AbstractThe Spitzer mid-infrared (MIR) surveys, Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) and MIPSGAL have revealed a new view of the disk of the Milky Way. Hallmarks of the Galactic disk at MIR wavelengths with spatial resolution <2″ are bubbles/HII regions, infrared dark clouds, young stellar objects (YSOs)/star formation regions, diffuse dust and extended polycyclic aromatic hydrocarbons (PAHs), and more than 100 million publically available archived stars with measured flux densities at 7 wavelengths and positions accurate to 0.1″. At mid-IR wavelengths, the cool components in the Galaxy are preferentially bright and highlight physical processes that are not obvious at other wavelength regimes.

Laboratory investigations aimed at building a database for the interpretation of JWST spectra

2019 ◽  
Vol 15 (S350) ◽  
pp. 77-80
Author(s):  
Maria Elisabetta Palumbo ◽  
Giuseppe A. Baratta ◽  
Gleb Fedoseev ◽  
Daniele Fulvio ◽  
Carlotta Scirè ◽  
...  
Keyword(s):  
Thermal Processing ◽  
Laboratory Data ◽  
Cosmic Ray ◽  
Peak Position ◽  
Young Stellar Objects ◽  
Line Of Sight ◽  
High Quality ◽  
Stellar Objects ◽  
James Webb Space Telescope ◽  
Laboratory Investigations

AbstractThe James Webb Space Telescope (JWST) is expected to be launched in 2021. The JWST’s science instruments will provide high quality spectra acquired in the line of sight to young stellar objects whose interpretation will require a robust database of laboratory data. With this in mind, an experimental work is in progress in the Laboratory for Experimental Astrophysics in Catania to study the profile (shape, width, and peak position) of the main infrared bands of molecular species expected to be present in icy grain mantles. Our study also takes into account the modifications induced on icy samples by low-energy cosmic ray bombardment and by thermal processing. Here we present some recent results on deuterium hydrogen monoxide (HDO), N-bearing species, and carbon dioxide (CO2).

scholarly journals Identification of Class I Methanol Masers with Objects of Near and Mid-Infrared Bands and the Third Version of the Class I Methanol Maser (MMI) Catalog

2012 ◽  
Vol 8 (S287) ◽  
pp. 280-281
Author(s):  
Olga Bayandina ◽  
Irina Val'tts ◽  
Grigorii Larionov
Keyword(s):  
Galactic Plane ◽  
Short Wave ◽  
Class I ◽  
Young Stellar Objects ◽  
Bipolar Outflows ◽  
Stellar Objects ◽  
Mid Infrared ◽  
Dark Clouds ◽  
The Third ◽  
Methanol Masers

AbstractAn identification has been conducted of class I methanol masers with 1) short-wave infrared objects EGO (extended green objects) - tracer bipolar outflow of matter in young stellar objects, and 2) isolated pre-protostellar gas-dust cores of the interstellar medium which are observed in absorption in the mid-infrared in the Galactic plane. It is shown that more than 50% of class I methanol masers are identified with bipolar outflows, considering the EGO as bipolar outflows (as compared with the result of 22% in the first version of the MMI catalog that contains no information about EGO). 99 from 139 class I methanol masers (71%) are identified with SDC. Thus, it seems possible that the MMI can be formed in isolated self-gravitating condensations, which are the silhouette of dark clouds - IRDC and SDC.

Gemini Mid-Infrared Imaging of Massive Young Stellar Objects in NGC 3576

2003 ◽  
Vol 126 (5) ◽  
pp. 2411-2420 ◽  
Author(s):  
C. L. Barbosa ◽  
A. Damineli ◽  
R. D. Blum ◽  
P. S. Conti
Keyword(s):  
Infrared Imaging ◽  
Young Stellar Objects ◽  
Stellar Objects ◽  
Mid Infrared

scholarly journals MID-INFRARED SPECTRAL VARIABILITY ATLAS OF YOUNG STELLAR OBJECTS

2012 ◽  
Vol 201 (2) ◽  
pp. 11 ◽  
Author(s):  
Á. Kóspál ◽  
P. Ábrahám ◽  
J. A. Acosta-Pulido ◽  
C. P. Dullemond ◽  
Th. Henning ◽  
...  
Keyword(s):  
Young Stellar Objects ◽  
Spectral Variability ◽  
Stellar Objects ◽  
Mid Infrared ◽  
Infrared Spectral

scholarly journals Mid-infrared interferometry of massive young stellar objects

2008 ◽  
Vol 131 ◽  
pp. 012024 ◽  
Author(s):  
H Linz ◽  
B Stecklum ◽  
R Follert ◽  
Th Henning ◽  
R van Boekel ◽  
...  
Keyword(s):  
Young Stellar Objects ◽  
Stellar Objects ◽  
Mid Infrared ◽  
Infrared Interferometry

scholarly journals Characterising the Protostellar Population of the Magellanic Clouds with VLT/SINFONI

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
Jacob Ward ◽  
Joana Oliveira ◽  
Jacco van Loon ◽  
Marta Sewilo
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Emission Lines ◽  
Young Stellar Objects ◽  
Small Magellanic Cloud ◽  
Stellar Objects ◽  
Accretion Rates

AbstractAt distances of ~50 kpc and ~60 kpc for the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) respectively the Magellanic Clouds present us with a unique opportunity to study star formation in environments outside our own galaxy. Through Spitzer and Herschel photometry and spectroscopy, samples of Young Stellar Objects (YSOs) have been selected and spectroscpically confirmed in the Magellanic Clouds. Here we present some of the key results of our SINFONI K-band observations towards massive YSOs in the Magellanic Clouds. We resolve a number of Spitzer sources into multiple, previously unresolved, components and our analysis of emission lines suggest higher accretion rates and different disc properties compared with massive YSOs in the Milky Way.

scholarly journals Young Stellar Object Variability at IRAC Wavelengths: Clues to Star and Planet Formation

2009 ◽  
Vol 5 (H15) ◽  
pp. 734-734
Author(s):  
John R. Stauffer ◽  
Maria Morales ◽  
Luisa Rebull
Keyword(s):  
Light Curve ◽  
Density Profile ◽  
Hot Spot ◽  
Light Curves ◽  
Young Stellar Objects ◽  
Circumstellar Disk ◽  
Stellar Objects ◽  
Mid Infrared ◽  
Stellar Photosphere ◽  
Disk Plane

In Morales et al. (2009), we have recently investigated the mid-infrared (3.6 to 8.0 micron) variability of young-stellar objects (YSOs) using the IRAC camera on the Spitzer Space Telescope. Specifically, we obtained synoptic photometry of about 70 YSOs in the ~1 Myr old IC1396A globule over a 14 day period. More than half of the YSOs were detectably variable, with amplitudes up to about 0.2 magnitudes. About a third of these objects showed quasi-sinusoidal light curves with apparent periods of typically 5 to 12 days. At least two families of models can explain such light curves: (a) a Class II YSO with a photospheric hot spot which locally heats the inner circumstellar disk which is viewed from slightly above the disk plane, and (b) a YSO with a warped disk or with some other non-axisymmetric inner disk density profile, also seen with a view angle slightly above the disk plane. The two models can both yield light curve shapes and amplitudes similar to what we observe in the mid-infrared, but produce very different light curves at shorter wavelengths dominated by the stellar photosphere. Because we only had IRAC photometry for IC1396A, we were not able to discriminate between the two models for this set of data.

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