Abstract
We have determined the mass profiles of dark halos in 83 objects observed by ASCA. The point-spread function of the X-ray telescope was deconvoled by the Richardson-Lucy algorithm, and the temperature profiles were calculated to obtain the mass profiles. The derived mass profiles are consistent with the Navarro, Frenk, & White model in (0.01-1.0)r virial . We found a good correlation between the scale radius r s and the characteristic mass density δ c , which indicates the self-similarity of dark halos. The spectrum index of primordial density fluctuation, P(k) ∝ k n , was determined from the slope of the r s -δ c relation. For M 200 = 10 12 -10 15 M ⊙ , our analysis gives n = -1.2 ± 0.3 with a confidence level of 90%. The mass density of dark halos is a good indicator of the mean mass density of the universe at the time when the halos were assembled, z = z f . Assuming δ c ∝ (1 + z f ) 3 , we have determined the epoch when each dark halo was assembled. Our analysis indicates that the field elliptical galaxies and groups of galaxies formed approximately at 1 - z f ≃ 15 and at 1 + z f ≃ 7-10, respectively.
| Original language | English |
|---|---|
| Journal | Astrophysical Journal |
| Volume | 537 |
| Issue number | 2 PART 2 |
| Publication status | Published - 10-07-2000 |
| Externally published | Yes |
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All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
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The observed mass profiles of dark halos and the formation epoch of galaxies. / Sato, Shinji; Akimoto, Fumie; Furuzawa, Akihiro; Tawara, Yuzuru; Watanabe, Manabu; Kumai, Yasuki.
In: Astrophysical Journal, Vol. 537, No. 2 PART 2, 10.07.2000.Research output: Contribution to journal › Article
TY - JOUR
T1 - The observed mass profiles of dark halos and the formation epoch of galaxies
AU - Sato, Shinji
AU - Akimoto, Fumie
AU - Furuzawa, Akihiro
AU - Tawara, Yuzuru
AU - Watanabe, Manabu
AU - Kumai, Yasuki
PY - 2000/7/10
Y1 - 2000/7/10
N2 - We have determined the mass profiles of dark halos in 83 objects observed by ASCA. The point-spread function of the X-ray telescope was deconvoled by the Richardson-Lucy algorithm, and the temperature profiles were calculated to obtain the mass profiles. The derived mass profiles are consistent with the Navarro, Frenk, & White model in (0.01-1.0)r virial . We found a good correlation between the scale radius r s and the characteristic mass density δ c , which indicates the self-similarity of dark halos. The spectrum index of primordial density fluctuation, P(k) ∝ k n , was determined from the slope of the r s -δ c relation. For M 200 = 10 12 -10 15 M ⊙ , our analysis gives n = -1.2 ± 0.3 with a confidence level of 90%. The mass density of dark halos is a good indicator of the mean mass density of the universe at the time when the halos were assembled, z = z f . Assuming δ c ∝ (1 + z f ) 3 , we have determined the epoch when each dark halo was assembled. Our analysis indicates that the field elliptical galaxies and groups of galaxies formed approximately at 1 - z f ≃ 15 and at 1 + z f ≃ 7-10, respectively.
AB - We have determined the mass profiles of dark halos in 83 objects observed by ASCA. The point-spread function of the X-ray telescope was deconvoled by the Richardson-Lucy algorithm, and the temperature profiles were calculated to obtain the mass profiles. The derived mass profiles are consistent with the Navarro, Frenk, & White model in (0.01-1.0)r virial . We found a good correlation between the scale radius r s and the characteristic mass density δ c , which indicates the self-similarity of dark halos. The spectrum index of primordial density fluctuation, P(k) ∝ k n , was determined from the slope of the r s -δ c relation. For M 200 = 10 12 -10 15 M ⊙ , our analysis gives n = -1.2 ± 0.3 with a confidence level of 90%. The mass density of dark halos is a good indicator of the mean mass density of the universe at the time when the halos were assembled, z = z f . Assuming δ c ∝ (1 + z f ) 3 , we have determined the epoch when each dark halo was assembled. Our analysis indicates that the field elliptical galaxies and groups of galaxies formed approximately at 1 - z f ≃ 15 and at 1 + z f ≃ 7-10, respectively.
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M3 - Article
VL - 537
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2 PART 2
ER -