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NGC 4258
NGC 4258 taken by [[]].
Observation data (J2000 epoch)
Constellation	Canes Venatici
Right ascension	12h 18m 57.620s
Declination	+47° 18′ 13.39″
Redshift	0.001541
Heliocentric radial velocity	462km/s
Distance	21.73 M[light-year
Apparent magnitude (B)	9.14
Characteristics
Type	SAB(s)bc
Other designations
B3 1216+475, 7C 121635.39+473404.00, 7C 121626.19+473526.00, 7C 121620.39+473545.00, GB1 1216+476, GB6 B1216+4735, 87GB 121625.0+473537, LEDA 39600, 2MASX J12185761+4718133, MCG+08-22-104, MY 121625.0+471813.7, NGC 4258, OHIO N 427, PBC J1218.9+4718, 1RXP J121856.4+471755, RX J1219.0+4717, RX J1218.9+4718, 1RXS J121900.4+471747, SAX J1219.7+4721, SDSS J121857.50+471814.3, SWIFT J1218.9+4717, SWIFT J1219.4+4720, SWIFT J1219.0+4715, UGC 7353, UZC J121857.7+471820, VLSS J1218.9+4718, VV 448, WB 1216+4735, 2XMM J121857.5+471814, XSS J12190+4715, Z 243-67, Z 244-3, Z 1216.5+4735, [BAG2012] 184.7378+47.2874, [CHM2007] HDC 706 J121857.61+4718133, [CHM2007] LDC 867 J121857.61+4718133, [CPF88] 121629.0+473500.0, [KRL2007b] 111, [M98c] 121629.7+473455, [NKB95] N4258, [VDD93] 154, [VV2000c] J121857.5+471814, [VV2003c] J121857.5+471814, [VV2006c] J121857.5+471814, [VV2010c] J121857.5+471814, [VV98c] J121857.5+471814, [ZEH2003] RX J1219.0+4717 1

NGC 4258, also occasionally referred to as UGC 7353 and MGC +08-22-104 is a spiral galaxy located in the constellation of Canes Venatici at an aproximate distance of 27.73 Mly. NGC 4258 was discovered in 1781 by Pierre Mechain.

Observation

By monitoring observations of the nuclear water megamaser sources in NGC 4258, several geometric distance estimates were presented by Greenhill et al. (1995), Miyoshi et al. (1995), Herrnstein et al. (1999), Humphreys et al. (2005, 2008, 2013), Argon et al. (2007), and Riess et al. (2016). Humphreys et al. (2013) reported a distance value of d = 7.60 0.17 0.15 r s Mpc ((m M - = )0 29.404 0.049 0.043 r s), where errors with r and s represent aleatory errors and standarized errors, respectively. Mager et al. (2008) reported a TRGB distance to NGC 4258 based on photometry of the same HST images as used in this study. On the other hand, the revised TRGB calibration in this study yields total efficient uncertainty of 0.073 mag from NGC 4258 and 0.096 mag from the LMC as described in Section 3.

Structure

NGC 4258 is an essential galaxy for calibration of both the color dependence and the zero-point, because it shows a broad range of RGB color and hosts a megamaser, which is useful for geometric distance estimation. NGC 4258 has been observed with F555W and F814W filters. NGC 4258 is known to be a useful distance anchor because it hosts a water megamaser, which can be used as a powerful and precise geometric distance indicator.

See also

• Galaxy

External links

• NGC 4258 on SIMBAD