Table 1
Observed and derived parameters of Sagittarius dIrr.
| Parameter | Value | Notes |
|
|
||
| α0 | 19:29:59.9 | J2000a |
| δ0 | −17:40:49.4 | J2000a |
| l0 | 21.055° | Gal. long. |
| b0 | −16.289° | Gal. lat. |
| SGL | 221.275° | Supergal. long. |
| SGB | 55.516° | Supergal. lat. |
| E(B − V) | 0.107 ± 0.010 | Average ± σb |
| (m − M)0 | 25.16 ± 0.11 | |
| D | 1076 ± 55 kpc | |
| 1 arcsec | 5.2 pc | conv. factor at D = 1076 kpc |
| Vh | −78.5 ± 1 km s-2 | heliocentric velocityc |
| Vg | 8 km s-1 | galactocentric velocityc |
| ⟨[Fe/H]⟩ | −2.0 | from RGB colourd |
| ϵ | 0.50 | from LK00 |
| PA | 90° | from LK00 |
| μV(0) | 23.9 ± 0.1 mag/arcsec2 | central SBe |
| h | 1.1′ | Sérsic scale radius |
| rh | 1.1′ | Observedf |
| Vtot | 13.4 ± 0.1 | Observedf |
| M V | −12.1 ± 0.2 | |
| L V |
|
total V luminosity |
| MHI | 8.7 × 106 M⊙ | H i massg |
Notes.
Estimated by eye from HST-ACS images and verified to provide a more satisfactory centre of symmetry for the distribution of RGB stars w.r.t. the centre listed by M12. Our new centre is 13.5″ to the east and 9.4″ to the south of the M12 centre.
Average over the whole FoV from the reddening maps by Schlegel et al. (1998), as re-calibrated by Schlafly & Finkbeiner (2011) (regular grid covering the whole MOSAIC field with knots spaced by 2′).
From McConnachie (2012).
From the HST-ACS sample, see Sect. 3.
μV of the innermost point of the observed profile. Not corrected for extinction. The central SB of the best fitting Sersic profile is μV(0) = 23.3 mag/arcsec2.
From the numerical integration of the SB profile in rϵ. Vtot is in excellent agreement with the integrated magnitude of the best-fit Sersic model, Vtot = 13.3.
From Hunter et al. (2012).
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