<i>Odin</i>observations of ammonia in the Sgr A +50 km s<sup>-1</sup>cloud and circumnuclear disk

Sandqvist, Aa.; Frisk, U.; Lundin, Stefan; Nordh, L.; Olberg, M.; Olofsson, G.

doi:10.1051/0004-6361/201629954

Cited by 2 publications

(3 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This mechanism can naturally explain why the CNR in the GC presents an inner cavity and does not extend be-low 1.5-2 pc radius (Oka et al 2011;Liu et al 2012Liu et al , 2013Mills et al 2013;Smith & Wardle 2014;Harada et al 2015;Takekawa et al 2017;Mills et al 2017;Sandqvist et al 2017).…”

Section: Discussionmentioning

confidence: 98%

“…Molecular gas is also present in Milky Way's Galactic center (GC), where a dusty molecular torus -the socalled circumnuclear ring 7 (CNR) -orbits at about 2 pc from the SMBH (Serabyn et al 1986;Wright et al 2001;Christopher et al 2005;Oka et al 2011;Liu et al 2012Liu et al , 2013Mills et al 2013;Goicoechea et al 2013;Smith & Wardle 2014;Harada et al 2015;Takekawa et al 2017;Mills et al 2017;Sandqvist et al 2017;Goicoechea et al 2018).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Forming Circumnuclear Disks and Rings in Galactic Nuclei: A Competition Between Supermassive Black Hole and Nuclear Star Cluster

Trani

Mapelli

Ballone

2018

ApJ

View full text Add to dashboard Cite

We investigate the formation of circumnuclear gas structures from the tidal disruption of molecular clouds in galactic nuclei, by means of smoothed particle hydrodynamics simulations. We model galactic nuclei as composed of a supermassive black hole (SMBH) and a nuclear star cluster (NSC) and consider different mass ratios between the two components. We find that the relative masses of the SMBH and the NSC have a deep impact on the morphology of the circumnuclear gas. Extended disks form only inside the sphere of influence of the SMBH. In contrast, compact rings naturally form outside the SMBH's sphere of influence, where the gravity is dominated by the NSC. This result is in agreement with the properties of the Milky Way's circumnuclear ring, which orbits outside the SMBH sphere of influence. Our results indicate that compact circumnuclear rings can naturally form outside the SMBH sphere of influence.

show abstract

Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Forming Circumnuclear Disks and Rings in Galactic Nuclei: A Competition Between Supermassive Black Hole and Nuclear Star Cluster

Trani

Mapelli

Ballone

2018

ApJ

View full text Add to dashboard Cite

show abstract

“…Gorski et al 2018), the centre of our Galaxy (e.g. Sandqvist et al 2017), and in the Solar System planets. It was first detected in the interstellar medium towards the Galactic centre by Cheung et al (1968) through its J = 1, K = 1 inversion transition.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of the binding energy of NH₃ on different types of ice and its impact on the snow line of NH₃ and H₂O

Kakkenpara Suresh,

Dulieu,

Vitorino

et al. 2024

A&A

View full text Add to dashboard Cite

Nitrogen-bearing molecules (such as N$_ $H$^ $ and NH$_ $) are excellent tracers of high-density and low-temperature regions, such as dense cloud cores. Notably, they could help advance the understanding of snow lines in protoplanetary discs and the chemical evolution of comets. However, much remains unknown about the chemistry of N-bearing molecules on grain surfaces, which could play an important role in their formation and evolution. In this work, we experimentally study the behaviour of NH$_ $ on surfaces that mimic grain surfaces under interstellar conditions in the presence of some other major components of interstellar ices (i.e. H$_2$O, CO$_2$, CO). We measure the binding energy distributions of NH$_ $ from different H$_ $O ice substrates and also investigate how it could affect the NH$_ $ snow line in protoplanetary discs. We performed laboratory experiments using the ultra-high vacuum (UHV) set-up VENUS (VErs des NoUvelles Syntheses). We co-deposited NH$_ $ along with other adsorbates (H$_ $O, 13CO, and CO$_ $) and performed temperature programmed desorption (TPD) and temperature programmed-during exposure desorption (TP-DED) experiments. The experiments were monitored using a quadrupole mass spectrometer (QMS) and a Fourier transform reflection absorption infrared spectrometer (FT-RAIRS). We obtained the binding energy distribution of NH$_ $ on crystalline ice (CI) and compact amorphous solid water ice (c-ASW) by analysing the TPD profiles of NH$_ $ obtained after depositions on these substrates. In the co-deposition experiments, we observed a significant delay in the desorption and a decrease of the desorption rate of NH$_ $ when H$_ $O is introduced into the co-deposited mixture of NH$_ $-13CO or NH$_ $-CO$_ $, which is not the case in the absence of H$_ $O. Secondly, we noticed that H$_ $O traps roughly 5-9$<!PCT!>$ of the co-deposited NH$_ $, which is released during the phase change of water from amorphous to crystalline. Thirdly, we obtained a distribution of binding energy values of NH$_ $ on both ice substrates instead of an individual value, as assumed in previous works. For CI, we obtained an energy distribution between 3780K and 4080K, and in the case of amorphous ice, the binding energy values were distributed between 3630K and 5280K; in both cases we used a pre-exponential factor of A = 1.94times 1015s$^ From our experiments, we conclude that the behaviour of NH$_ $ is significantly influenced by the presence of water, owing to the formation of hydrogen bonds with water, in line with quantum calculations. This interaction, in turn, preserves NH$_ $ on the grain surfaces longer and up to higher temperatures, making it available closer to the central protostar in protoplanetary discs than previously thought. It explains well why the NH$_ $ freeze-out in pre-stellar cores is efficient. When present along with H$_ $O, CO$_2$ also appears to impact the behaviour of NH$_ $, retaining it at temperatures similar to those of water. This may impact the overall composition of comets, particularly the desorption of molecules from their surface as they approach the Sun.

show abstract

Odinobservations of ammonia in the Sgr A +50 km s^-1cloud and circumnuclear disk

Abstract: Context. The Odin satellite is now into its sixteenth year of operation

Cited by 2 publications

References 27 publications

Forming Circumnuclear Disks and Rings in Galactic Nuclei: A Competition Between Supermassive Black Hole and Nuclear Star Cluster

Forming Circumnuclear Disks and Rings in Galactic Nuclei: A Competition Between Supermassive Black Hole and Nuclear Star Cluster

Experimental study of the binding energy of NH₃ on different types of ice and its impact on the snow line of NH₃ and H₂O

Contact Info

Product

Resources

About

Odinobservations of ammonia in the Sgr A +50 km s-1cloud and circumnuclear disk

Abstract: Context. The Odin satellite is now into its sixteenth year of operation

Cited by 2 publications

References 27 publications

Forming Circumnuclear Disks and Rings in Galactic Nuclei: A Competition Between Supermassive Black Hole and Nuclear Star Cluster

Forming Circumnuclear Disks and Rings in Galactic Nuclei: A Competition Between Supermassive Black Hole and Nuclear Star Cluster

Experimental study of the binding energy of NH3 on different types of ice and its impact on the snow line of NH3 and H2O

Contact Info

Product

Resources

About

Odinobservations of ammonia in the Sgr A +50 km s^-1cloud and circumnuclear disk

Experimental study of the binding energy of NH₃ on different types of ice and its impact on the snow line of NH₃ and H₂O