Article
Astronomy & Astrophysics
L. Vacher, J. Chluba, J. Aumont, A. Rotti, L. Montier
Summary: The modeling and removal of foregrounds is a major challenge in the search for inflation signals in the cosmic microwave background (CMB). This work introduces a generalization of intensity moment expansion to the spin-2 field of linear polarization and demonstrates its application in modeling the frequency-dependent polarization angle.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
D. Rumble, J. Hatchell, H. Kirk, K. Pattle
Summary: Radiative feedback from OB stars in star-forming regions influences subsequent star formation by heating dust in the surrounding areas. The study quantifies the impact of different spectral type stars, with O-type stars showing the greatest temperature rises and heating extent, while B-type stars have a weaker heating effect. Even in local, 'low-mass' star-forming regions, 24% of the clumps are heated to at least 3 K above the base temperature expected from interstellar radiation heating, with a mean dust temperature of 24 K for heated clumps.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
V Pelgrims, J. F. Macias-Perez, F. Ruppin
Summary: The study focuses on the polarized Galactic synchrotron and thermal dust emission as a key tool to understand the Galactic magnetic field. A Markov chain Monte Carlo method is used to constrain the regular GMF geometry through simulations. By analyzing Planck polarization maps, the methodology proves effective in inferring the large-scale geometrical properties of the GMF, revealing a mean pitch angle of 27 degrees with 14% scatter.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Yuping Tang, Q. Daniel Wang, Grant W. Wilson
Summary: Through a Bayesian modeling and joint spectral energy distribution analysis, this study investigates the dust properties in the Central Molecular Zone of our Galaxy, revealing an increasing trend of dust spectral index beta towards dense peaks. This environmental dependence of beta could have significant implications for the determination of dust temperature in other studies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
A. D. P. Howard, A. P. Whitworth, M. J. Griffin, K. A. Marsh, M. W. L. Smith
Summary: The PPMAP algorithm reanalyzed observations of the L1688 and L1689 subregions of the Ophiuchus molecular cloud, delivering high-resolution maps and more accurate dust optical depths. Most filaments and pre-stellar cores are located in regions with high N-H2 values, with some exceptions influenced by feedback from nearby stars. The study suggests that most starless cores are likely to disperse instead of evolving into pre-stellar cores.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
F. D. Priestley, I De Looze, M. J. Barlow
Summary: In the diffuse interstellar medium, small grains grow by efficiently accreting positively charged ions until they become positively charged and growth is halted. Gas-phase depletions are significantly overestimated when assuming a constant grain size distribution under diffuse ISM conditions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
L. Vacher, J. Aumont, L. Montier, S. Azzoni, F. Boulanger, M. Remazeilles
Summary: Accurate characterization of polarized dust emission is crucial for the study of the cosmic microwave background primordial B-modes. Future surveys need to consider the spectral variations of dust and use innovative parameterization methods to avoid biases in the analysis. This paper applies a moment expansion of the dust spectral energy distribution and introduces the expansion of the cross-angular power spectra in both spectral index and temperature, achieving an unbiased measurement of the tensor-to-scalar ratio.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Zainab Awad, Serena Viti
Summary: Observations of diffuse clouds have found high abundances of simple hydrocarbons, challenging conventional gas-phase chemical models. Recent experimental results suggest that photodecomposition of hydrogenated amorphous carbon (HAC) and solid hexane can release a range of hydrocarbons into the gas phase. This study explores the feasibility of a 'top-down' or degradation mechanism for the formation of simple hydrocarbons in diffuse clouds.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Sandeep Kumar Acharya, Jiten Dhandha, Jens Chluba
Summary: The excess radio background observed at similar to 0.1-10GHz has sparked scientific debate in recent years. A recent hypothesis suggests that the soft photon emission from accreting primordial black holes could explain this signal. However, our study shows that the expected ultraviolet photon emission from these accreting black holes would fully ionize the universe at z > 6, thereby diminishing the 21-cm absorption signature at z similar to 20 and conflicting with the current limits of cosmic microwave background anisotropy and average spectral distortion.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Kate Pattle, Shih-Ping Lai, Melvyn Wright, Simon Coude, Richard Plambeck, Thiem Hoang, Ya-Wen Tang, Pierre Bastien, Chakali Eswaraiah, Ray S. Furuya, Jihye Hwang, Shu-ichiro Inutsuka, Kee-Tae Kim, Florian Kirchschlager, Woojin Kwon, Chang Won Lee, Sheng-Yuan Liu, Aran Lyo, Nagayoshi Ohashi, Mark G. Rawlings, Mehrnoosh Tahani, Motohide Tamura, Archana Soam, Jia-Wei Wang, Derek Ward-Thompson
Summary: ALMA Band 7 polarization observations of the OMC-1 region of the Orion molecular clouds showed that the polarization pattern was influenced by the radiation field of the high-mass protostar Orion Source I. The optically thick disc of the protostar likely caused polarization from dust self-scattering, revealing a concentric geometry around Source I. The extreme luminosity of Source I may cause grains to precess around the radiation anisotropy vector, supporting the emission from the Source I outflow cavity wall.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Haoyu Fan, Madison Schwartz, Amin Farhang, Nick L. J. Cox, Pascale Ehrenfreund, Ana Monreal-Ibero, Bernard H. Foing, Farid Salama, Klay Kulik, Heather MacIsaac, Jacco Th van Loon, Jan Cami
Summary: More than 500 diffuse interstellar bands (DIBs) have been observed and studied to reveal the nature of their carriers. Researchers have found anticorrelated DIB pairs and redefined DIB families using clustering algorithms. They also discovered a continuous sequence of DIBs and identified at least two factors influencing the dissimilarities between them.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Tirthankar Roy Choudhury, Suvodip Mukherjee, Sourabh Paul
Summary: By comparing predictions of a physical seminumerical model with CMB data, constraints on allowed reionization histories were studied, leading to the determination of tight constraints on parameters such as reionization duration and halo mass. Analysis showed implications for future CMB surveys and 21 cm studies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
V Pelgrims, S. E. Clark, B. S. Hensley, G. Panopoulou, V Pavlidou, K. Tassis, H. K. Eriksen, I. K. Wehus
Summary: This study presents evidence for LOS frequency decorrelation in Planck data, utilizing HI emission measurements to detect this phenomenon. The detection of LOS frequency decorrelation at high Galactic latitudes in polarized data is significant, attributed to a combination of frequency variation in polarization angle and depolarization effects.
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
Martin Glatzle, Luca Graziani, Benedetta Ciardi
Summary: The presence of charged dust grains has a significant impact on the physical evolution of the interstellar medium, but this process is still poorly explored in numerical simulations. A novel implementation of grain charging in a radiative transfer code is introduced in this study, and its effects on grain properties and charge distribution are evaluated. The findings open up possibilities for further studies on the physical evolution of the dusty ISM accessible through observations of galaxies at different redshifts.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
