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Cited by 428

The DOI matches its Crossref record; 71 of the 71 references it cites were found in a registry or an index.

Advection‐dominated Accretion Model of Sagittarius A*: Evidence for a Black Hole at the Galactic Center

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Narayan, Ramesh, Mahadevan, Rohan, Grindlay, Jonathan E., Popham, Robert G., Gammie, Charles·1998·The Astrophysical Journal
DOI 10.1086/305070
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Abstract

Sagittarius A*, which is located at the Galactic center, is a puzzling source. It has a mass of M = (2.5 ± 0.4) × 10 6 M ☉ , which makes it an excellent black hole candidate. Observations of stellar winds and other gas flows in its vicinity suggest a mass accretion rate of ≳ few × 10 −6 M ☉ yr -1 . However, such an accretion rate would imply a luminosity greater than 10 40 ergs -1 if the radiative efficiency is the usual 10%, whereas observations indicate a bolometric luminosity less than 10 37 ergs -1 . The spectrum of Sgr A* is unusual, with emission extending over many decades of wavelength. We present a model of Sgr A* that is based on a two-temperature optically thin advection-dominated accretion flow. The model is consistent with the estimated M and and fits the observed fluxes in the centimeter/millimeter and X-ray bands, as well as upper limits in the submillimeter and infrared bands; the fit is less good in the radio spectrum below 86 GHz and in γ-rays above 100 MeV. The very low luminosity of Sgr A* is explained naturally in the model by means of advection. Most of the viscously dissipated energy is advected into the central mass by the accreting gas, and therefore the radiative efficiency is extremely low, ~5 × 10 -6 . A critical element of the model is the presence of an event horizon at the center that swallows the advected energy. The success of the model could thus be viewed as confirmation that Sgr A* is a black hole.

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Metadata

Authors
Narayan, R., Mahadevan, R., Grindlay, J. E., Popham, R. G., & Gammie, C.
Venue
The Astrophysical Journal
Publisher
American Astronomical Society
Published
1998-01-10
Volume
492
Issue
2
Pages
554-568
ISSN
  • 0004-637X (ISSN-L)
  • 1538-4357
DOI
10.1086/305070
OpenAlex
W2064965371
Cited by
428
References
71
FWCI
29.94
Type
journal article
Language
en
Open access
bronze

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CoChat. (2026). Citation check: Advection‐dominated Accretion Model of Sagittarius A*: Evidence for a Black Hole at the Galactic Center. https://app.cochat.ai/papers/10.1086/305070
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Narayan, R., Mahadevan, R., Grindlay, J. E., Popham, R. G., & Gammie, C. (1998). Advection‐dominated Accretion Model of Sagittarius A*: Evidence for a Black Hole at the Galactic Center. The Astrophysical Journal. https://doi.org/10.1086/305070

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