AGN feeding and feedback in Fornax A Maccagni, F. M.; Serra, P.; Gaspari, M. ...
Astronomy and astrophysics (Berlin),
12/2021, Letnik:
656
Journal Article
Recenzirano
We present a multi-wavelength study of the gaseous medium surrounding the nearby active galactic nucleus (AGN), Fornax A. Using MeerKAT, ALMA, and MUSE observations, we reveal a complex distribution ...of the atomic (H I ), molecular (CO), and ionised gas in its centre and along the radio jets. By studying the multi-scale kinematics of the multi-phase gas, we reveal the presence of concurrent AGN feeding and feedback phenomena. Several clouds and an extended 3 kpc filament – perpendicular to the radio jets and the inner disk ( r ≲ 4.5 kpc) – show highly-turbulent kinematics, which likely induces non-linear condensation and subsequent chaotic cold accretion (CCA) onto the AGN. In the wake of the radio jets and in an external ( r ≳ 4.5 kpc) ring, we identify an entrained massive (∼10 7 M ⊙ ) multi-phase outflow ( v OUT ∼ 2000 km s −1 ). The rapid flickering of the nuclear activity of Fornax A (∼3 Myr) and the gas experiencing turbulent condensation raining onto the AGN provide quantitative evidence that a recurrent, tight feeding and feedback cycle may be self-regulating the activity of Fornax A, in agreement with CCA simulations. To date, this is one of the most in-depth probes of such a mechanism, paving the way to apply these precise diagnostics to a larger sample of nearby AGN hosts and their multi-phase inter stellar medium.
GASP Ramatsoku, M.; Serra, P.; Poggianti, B. M. ...
Astronomy and astrophysics (Berlin),
08/2020, Letnik:
640
Journal Article
Recenzirano
We present atomic hydrogen (H
I
) observations with the
Jansky
Very Large Array of one of the jellyfish galaxies in the GAs Stripping Phenomena sample, JO201. This massive galaxy (
M
*
= 3.5 × 10
...10
M
⊙
) is falling along the line-of-sight towards the centre of a rich cluster (
M
200
∼ 1.6 × 10
15
M
⊙
,
σ
cl
∼ 982 ± 55 km s
−1
) at a high velocity ≥3363 km s
−1
. Its H
α
emission shows a ∼40 kpc tail, which is closely confined to its stellar disc and a ∼100 kpc tail extending further out. We find that H
I
emission only coincides with the shorter clumpy H
α
tail, while no H
I
emission is detected along the ∼100 kpc H
α
tail. In total, we measured an H
I
mass of
M
HI
= 1.65 × 10
9
M
⊙
, which is about 60% lower than expected based on its stellar mass and stellar surface density. We compared JO201 to another jellyfish in the GASP sample, JO206 (of a similar mass but living in a ten times less massive cluster), and we find that they are similarly H
I
-deficient. Of the total H
I
mass in JO201, about 30% lies outside the galaxy disc in projection. This H
I
fraction is probably a lower limit since the velocity distribution shows that most of the H
I
is redshifted relative to the stellar disc and could be outside the disc. The global star formation rate (SFR) analysis of JO201 suggests an enhanced star formation for its observed H
I
content. The observed SFR would be expected if JO201 had ten times its current H
I
mass. The disc is the main contributor of the high star formation efficiency at a given H
I
gas density for both galaxies, but their tails also show higher star formation efficiencies compared to the outer regions of field galaxies. Generally, we find that JO201 and JO206 are similar based on their H
I
content, stellar mass, and star formation rate. This finding is unexpected considering their different environments. A toy model comparing the ram pressure of the intracluster medium (ICM) versus the restoring forces of these galaxies suggests that the ram pressure strength exerted on them could be comparable if we consider their 3D orbital velocities and radial distances relative to the clusters.
Bridging the Social Gap: Perspectives on Dalit Empowerment addresses four interrelated issues. It conceptualises exclusion-linked deprivation of excluded and indigenous groups in Indian society and ...elaborates the concept and meaning of social exclusion in general, and of caste-, untouchability- and ethnicity-based exclusion in particular. It then presents the status of disadvantaged groups of Dalit and Adivasi and captures inter-social group inequalities in the attainment of human development. It then goes on to analyse factors associated with high deprivation of these disadvantaged groups in terms of low access to resources, employment, education and social needs. Finally, it highlights the role of caste discrimination in economic, civil and political spheres in the persistence of group inequalities. All these issues have been explained using simple language; relevant and recent data; case studies; news highlights related to civil, social, economic and political rights violation for easy and better understanding of readers.
This article reviews the trends in government subsidies and investments in and for Indian agriculture; develops a conceptual framework and a model to assess the impact of various subsidies and ...investments on agricultural growth and poverty reduction; and presents reform options with regard to re-prioritizing government spending. Subsidies in credit, fertilizer, and irrigation have been crucial for small farmers to adopt new technologies particularly during the initial stage of the green revolution in the late 1960s and 1970s. But it is now investments in agricultural research, education, and rural roads that are the three most effective public spending items in promoting agricultural growth and reducing poverty.
The explosion of English in India formed a new generation and voice in which Indians speaks. Since Indian Renaissance, Indian writers writing in English have been making manifold contribution to the ...World literature. ...from the above mentioned survey, the response of the teachers and learners to teach English through IWE is positive to some extent. ...IWE may serve as an effective tool for teaching and learning English in rural India. ...a study of such and other works may be of great help to the teachers and learners of English.
This book provides a detailed and comprehensive account of the status of Dalits in contemporary India. It delineates their economic and social status and charts the changes since 1947 with respect to ...important indicators of human development.By providing statewise (and where possible, district level) data, author Sukhadeo Thorat reveals the inter-state patterns and intra-state variations of their status across the country. Using comparative methodology, the book also brings out the disparities between Dalits and the high castes in society, all the while providing explanations for these inequalities in the present context. The detailed conclusion outlines the policies required to facilitate the empowerment of Dalits.The book covers all the important parameters including:Demographic profile; Gender; Employment; Ownership of land; Poverty; Literacy and education; Health; Civil rights
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