Article
Astronomy & Astrophysics
Fraser M. Smith, Tina A. Harriott, Daniel Majaess, Lou Massa, Cherif F. Matta
Summary: Analysis of observations from the Apache Point Observatory Catalog of Optical Diffuse Interstellar Bands (DIBs) revealed highly correlated pairs in terms of their equivalent widths, aiding in the identification of common carriers. Further research is needed to explore the novel relations between certain DIBs and investigate potential DIB carriers.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
M. Houde, B. Lankhaar, F. Rajabi, M. A. Chamma
Summary: In this discussion, we explore the existence of elliptical polarization in rotational spectral lines of CO and other molecules within the framework of the Anisotropic Resonant Scattering (ARS) model. We demonstrate that the effect of ARS can lead to the transformation of background linear polarization into circular polarization (Faraday conversion), as well as the occurrence of Faraday rotation and the generation of elliptically polarized signals in an initially unpolarized radiation field. This collective behavior is a result of favoring forward scattering over other modes due to a large number of molecules acting as a diffraction ensemble.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
G. A. Galazutdinov, J. Krelowski
Summary: This paper describes the specific profile of the narrowest known strong diffuse interstellar band (DIB) 6196 & ANGS; in objects belonging to the Sco OB2 association. The split and broadened profiles of the 6196 DIB in reddened Sco OB2 objects cannot be explained by the presence of multiple clouds with different radial velocities. The split profiles may be composed of the band center and its head of an unknown molecule.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Arshia M. Jacob, Karl M. Menten, Helmut Wiesemeyer, Gisela N. Ortiz-Leon
Summary: Interferometric observations of CH radio emission lines towards star-forming regions reveal unexpected emission characteristics, suggesting unique excitation conditions and physical properties. Gas densities and temperatures inferred from the observations indicate a possible formation mechanism for CH in heated interstellar material, shedding light on the molecular dynamics within these regions. Additionally, statistical equilibrium calculations show consistency with previous theoretical predictions, providing insight into the excitation processes of CH in the interstellar medium.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Yang Yang, Yao Wang, Zhibo Jiang, Zhiwei Chen
Summary: The study focuses on understanding the initial stages of star formation through investigating the physical and chemical properties of gas infall motion in molecular clumps. The FTS wide-sideband mode of the IRAM 30-m telescope was used to observe nine infall sources with significant double-peaked blue line profiles. Molecular line data was obtained, and multiple molecules and isotopic transition lines were identified in these sources. Chemical simulations were used to fit the observed molecular abundances, indicating that most sources are in the early HMPO stage with temperatures around several 10 K.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
F. Fontani, A. Schmiedeke, A. Sanchez-Monge, L. Colzi, D. Elia, V. M. Rivilla, M. T. Beltran, L. Bizzocchi, P. Caselli, L. Magrini, D. Romano
Summary: The study reveals that the chemical properties of the outer star-forming regions of the Galaxy are similar to those of the inner and local regions. Methanol (CH3OH) is detected in the observed targets, and its emission is associated with an extended envelope, indicating that it mainly comes from a cold and quiescent region. The relative abundance of CH3OH shows good correlations with that of H2CO, but not with HCO. These findings have significant implications for understanding the organic and possibly pre-biotic chemistry in the outermost star-forming regions of the Galaxy.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
D. Colombo, C. Koenig, J. S. Urquhart, F. Wyrowski, M. Mattern, K. M. Menten, M-Y Lee, J. Brand, M. Wienen, P. Mazumdar, F. Schuller, S. Leurini
Summary: Filaments are common features of the molecular interstellar medium and play a key role in star formation. Recent studies have found large-scale filaments in both the inner and outer Milky Way, with those in the outer region showing lower masses compared to the inner region. This suggests that Milky Way dynamics can create elongated features even with lower gas supply in the Galactic outskirts.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Leander Schlarmann, Bernard Foing, Jan Cami, Haoyu Fan
Summary: The study investigated the correlations between the strengths of the two strongest C-60(+) DIBs and their environmental behavior. It was found that there is a high correlation between the strengths of the C-60(+) DIBs, and the behavior of these correlated bands differs significantly from other DIBs in different environments.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
M. Wienen, C. M. Brunt, C. L. Dobbs, D. Colombo
Summary: Expanding (sub)millimetre capabilities to high angular resolution with interferometers enables the resolution of giant molecular clouds in nearby galaxies. By remapping CO-C-12 data along the Perseus spiral arm in the Milky Way, at a common distance to an observer outside the galaxy, important insights into the structure of the arm, including thickness, centroid position, and mass distribution, were determined.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Heather MacIsaac, Jan Cami, Nick L. J. Cox, Amin Farhang, Jonathan Smoker, Meriem Elyajouri, Rosine Lallement, Peter J. Sarre, Martin A. Cordiner, Haoyu Fan, Klay Kulik, Harold Linnartz, Bernard H. Foing, Jacco Th van Loon, Giacomo Mulas, Keith T. Smith
Summary: This study analyzes the profiles of diffuse interstellar bands (DIBs) and explores their systematic variations to understand the properties of the molecules responsible for these bands. The researchers found that the rotational excitation temperatures and the sizes of the DIB carriers show correlated changes, indicating the potential to constrain molecular properties based on the variations of the DIB profiles. The estimated sizes of the DIB carriers range from 7-9 carbon atoms to 77-114 carbon atoms.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
F. Fontani, L. Colzi, L. Bizzocchi, V. M. Rivilla, D. Elia, M. T. Beltran, P. Caselli, L. Magrini, A. Sanchez-Monge, L. Testi, D. Romano
Summary: This paper presents a new observational project called CHEMOUT, which aims to investigate the chemical composition in star-forming regions of the outer Galaxy. The results show that organic molecules and tracers of protostellar activity are ubiquitous in the low metallicity environment of the outer Galaxy.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Rong Xuan Zang, Alexandros Maragkoudakis, Els Peeters
Summary: This study presents a detailed investigation on the emission properties of polycyclic aromatic hydrocarbons (PAHs) in the circumnuclear and extranuclear regions of M51a using Spitzer-IRS observations. The study reveals that the hardness of the radiation field has a stronger impact on PAH emissions compared to metallicity, and smaller/mid-sized PAHs are processed at a higher rate than larger PAHs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Susana Iglesias-Groth, Martina Marin-Dobrincic
Summary: We conducted Spitzer 10-34 μm spectroscopic observations of the diffuse gas in the inner region of the star-forming region IC 348 of the Perseus Molecular Cloud. Our findings reveal the presence of various common molecules and carbonaceous molecules, some of which may play a crucial role in the production of more complex hydrocarbons. The study also highlights the rich and diverse molecular content of IC 348, including the presence of PAHs and fullerenes C-60 and C-70. The spectroscopic capabilities of JWST may provide more detailed information on the spatial distribution of these molecules and expand the search for complex hydrocarbons.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
R. E. Miura, D. Espada, A. Hirota, C. Henkel, S. Verley, M. I. N. Kobayashi, S. Matsushita, F. P. Israel, B. Vila-Vilaro, K. Morokuma-Matsui, J. Ott, C. Vlahakis, A. B. Peck, S. Aalto, M. R. Hogerheijde, N. Neumayer, D. Iono, K. Kohno, H. Takemura, S. Komugi
Summary: A census of giant molecular clouds (GMCs) in the inner region of the Centaurus A galaxy reveals similarities with GMC properties in spiral galaxies but distinct features in the circumnuclear disc, possibly influenced by the active galactic nucleus and/or shear motions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
S. Spezzano, O. Sipilae, P. Caselli, S. S. Jensen, S. Czakli, L. Bizzocchi, J. Chantzos, G. Esplugues, A. Fuente, F. Eisenhauer
Summary: Deuteration plays a crucial role in understanding the interstellar chemical processes, and this study focuses on the D/H ratio in H2CS across the L1544 prototypical pre-stellar core. The results show that the maximum deuterium fractionation for the first deuteration of H2CS is around 30% and is located at a distance of about 10,000 AU from the dust peak. The second deuteration of H2CS and H2CO is more efficient, leading to a higher deuterium fractionation. The large deuteration of H2CO and H2CS observed in protostellar cores and comets is likely inherited from the pre-stellar phase. However, the reaction network for the formation of doubly deuterated H2CS and H2CO is not yet complete according to the comparison with state-of-the-art chemical models.
ASTRONOMY & ASTROPHYSICS
(2022)
Editorial Material
Multidisciplinary Sciences
Takeshi Oka
Article
Astronomy & Astrophysics
Takeshi Oka, Daniel E. Welty, Sean Johnson, Donald G. York, Julie Dahlstrom, L. M. Hobbs
ASTROPHYSICAL JOURNAL
(2013)
Article
Astronomy & Astrophysics
Miwa Goto, T. R. Geballe, Nick Indriolo, Farhad Yusef-Zadeh, Tomonori Usuda, Thomas Henning, Takeshi Oka
ASTROPHYSICAL JOURNAL
(2014)
Review
Chemistry, Multidisciplinary
Takeshi Oka
Article
Chemistry, Physical
Keiichi Tanaka, Kensuke Harada, Takeshi Oka
JOURNAL OF PHYSICAL CHEMISTRY A
(2013)
Article
Chemistry, Physical
Miwa Goto, Nick Indriolo, T. R. Geballe, T. Usuda
JOURNAL OF PHYSICAL CHEMISTRY A
(2013)
Editorial Material
Chemistry, Physical
Takeshi Oka
JOURNAL OF PHYSICAL CHEMISTRY A
(2013)
Editorial Material
Multidisciplinary Sciences
Takeshi Oka
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2019)
Editorial Material
Multidisciplinary Sciences
T. R. Geballe, T. Oka, M. Goto
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2019)
Article
Astronomy & Astrophysics
Takeshi Oka, T. R. Geballe
Summary: Using the relation between radial expansion velocity and distance from Sgr A* in the CMZ, this study estimates the physical depths of Star iota and two Sgr B2 far-infrared continuum sources relative to the location of Sgr A*. The study finds that Sgr B2 is located towards the rear of the CMZ, contrary to previous models.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Takeshi Oka, T. R. Geballe
ASTROPHYSICAL JOURNAL
(2020)
Article
Astronomy & Astrophysics
Takeshi Oka, T. R. Geballe, Miwa Goto, Tomonori Usuda, Benjamin J. McCall, Nick Indriolo
ASTROPHYSICAL JOURNAL
(2019)
Article
Astronomy & Astrophysics
T. R. Geballe, E. Lambrides, B. Schlegelmilch, S. C. C. Yeh, M. Goto, Calvin Westrick, T. Oka, F. Najarro
ASTROPHYSICAL JOURNAL
(2019)
Article
Astronomy & Astrophysics
T. R. Geballe, R. E. Mason, T. Oka
ASTROPHYSICAL JOURNAL
(2015)
Correction
Astronomy & Astrophysics
Takeshi Oka, Daniel E. Welty, Sean Johnson, Donald G. York, Julie Dahlstrom, Lew Hobbs
ASTROPHYSICAL JOURNAL
(2014)