中文
相关论文

相关论文: Grain size limits derived from 3.6 {\mu}m and 4.5 …

200 篇论文

Context. The largest grains (0.5-1 micron) in the interstellar size distribution are efficient in scattering near- and mid-infrared radiation. These wavelengths are therefore particularly well suited to probe the still uncertain high-end of…

星系天体物理 · 物理学 2015-06-17 M. Andersen , J. Steinacker , W-F. Thi , L. Pagani , A. Bacmann , R. Paladini

Context. Using observations to deduce dust properties, grain size distribution, and physical conditions in molecular clouds is a highly degenerate problem. Aims. The coreshine phenomenon, a scattering process at 3.6 and 4.5 $\mu$m that…

Recently discovered scattered light at 3-5 $\mu$m from low-mass cores (so-called "coreshine") reveals the presence of grains around 1 $\mu$m, which is larger than the grains found in the low-density interstellar medium. But only about half…

星系天体物理 · 物理学 2015-06-18 J. Steinacker , M. Andersen , W. -F. Thi , A. Bacmann

We investigate the condition for the formation of micron-sized grains in dense cores of molecular clouds. This is motivated by the detection of the mid-infrared emission from deep inside a number of dense cores, the so-called `coreshine,'…

星系天体物理 · 物理学 2015-06-16 Hiroyuki Hirashita , Zhi-Yun Li

The recently discovered coreshine effect can aid in exploring the core properties and in probing the large grain population of the ISM. We discuss the implications of the coreshine detected from the molecular cloud core L1506C in the Taurus…

星系天体物理 · 物理学 2015-06-19 J. Steinacker , C. W. Ormel , M. Andersen , A. Bacmann

Context: Observations of scattered light in the 1-5 $\mu$m range have revealed dust grains in molecular cores with sizes larger than commonly inferred for the diffuse interstellar medium. It is currently unclear whether these grains are…

星系天体物理 · 物理学 2014-09-05 M. Andersen , W-F. Thi , J. Steinacker , N. Tothill

Cold molecular clouds are the birthplaces of stars and planets, where dense cores of gas collapse to form protostars. The dust mixed in these clouds is thought to be made of grains of an average size of 0.1 micrometer. We report the…

星系天体物理 · 物理学 2011-10-20 Laurent Pagani , Jürgen Steinacker , Aurore Bacmann , Amelia Stutz , Thomas Henning

We study alignment of grains by radiative torques. We found steep rise of radiative torque efficiency as grain size increases. This allows larger grains that are known to exist within molecular clouds to be aligned by the attenuated and…

天体物理学 · 物理学 2009-11-11 J. Cho , A. Lazarian

We examine the cloud structure around the Planck detections in 71 fields observed with the Herschel SPIRE instrument. We wish to determine the general physical characteristics of the fields and to examine the morphology of the clouds where…

The sizes of interstellar grains are widely distributed, ranging from a few angstroms to a few micrometers. The ultraviolet (UV) and optical extinction constrains the dust in the size range of a couple hundredth micrometers to several…

星系天体物理 · 物理学 2015-09-23 Shu Wang , Aigen Li , B. W. Jiang

We have studied the opacity of dust grains at submillimeter wavelengths by estimating the optical depth from imaging at 160, 250, 350, and 500 um from the Herschel Gould Belt Survey and comparing this to a column density obtained from the…

Density profiles of isolated cores derived from thermal dust continuum emission rely on models of dust properties, such as mass opacity, which are poorly constrained. With complementary measures from near-infrared extinction maps, we can…

We present a new approach aimed at constraining the typical size and optical properties of carbon dust grains in Circumstellar envelopes (CSEs) of carbon-rich stars (C-stars) in the Small Magellanic Cloud (SMC). To achieve this goal, we…

Interstellar dust grain growth in dense clouds and protoplanetary disks, even moderate, affects the observed interstellar ice profiles as soon as a significant fraction of dust grains is in the size range close to the wave vector at the…

星系天体物理 · 物理学 2022-10-26 Emmanuel Dartois , Jennifer A. Noble , Nathalie Ysard , Karine Demyk , Marin Chabot

Dust polarization induced by aligned grains is widely used to study magnetic fields in various environments, including star-forming regions. However, the question of to what optical depth grain alignment still exists in a dense molecular…

星系天体物理 · 物理学 2021-03-03 Thiem Hoang , Le Ngoc Tram , Hyeseung Lee , Pham Ngoc Diep , Nguyen Bich Ngoc

We observed the L1506 filament, which is located in the Taurus molecular complex, with the Herschel PACS and SPIRE instruments. Our aim is to prove the variation in grain properties along the entire length of the filament. In particular, we…

In this paper we study the effects of inclusions and porosities on the emission properties of silicate grains and compare the model curves with the observed infrared emission from circumstellar dust. We calculate the absorption efficiency…

太阳与恒星天体物理 · 物理学 2015-03-17 D. B. Vaidya , Ranjan Gupta

Context. Extinction and emission of dust models need for observational constraints to be validated. The coreshine phenomenon has already shown the importance of scattering in the 3 to 5 micron range and its ability to validate dust…

星系天体物理 · 物理学 2016-01-06 Charlène Lefèvre , Laurent Pagani , Michiel Min , Charles Poteet , Douglas Whittet

The size of dust grains, $a$, is key to the physical and chemical processes in circumstellar disks, but observational constraints of grain size remain challenging. (Sub)millimeter continuum observations often show a percent-level…

The DIRBE on the COBE spacecraft was designed primarily to conduct systematic search for an isotropic CIB in ten photometric bands from 1.25 to 240 microns. The results of that search are presented here. Conservative limits on the CIB are…

‹ 上一页 1 2 3 10 下一页 ›