Inner ring structures in galaxies as distance indicators. II - Calibration of inner ring diameters as quaternary indicators

Abstract

view Abstract Citations (35) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Inner ring structures in galaxies as distance indicators. II - Calibration of inner ring diameters as quaternary indicators Buta, R. ; de Vaucouleurs, G. Abstract The linear diameters Dr of the inner ring (r) and pseudo-ring (rs) structures in spiral galaxies of different morphological types and stage Sab to Sd (2≤T≤7) in the revised Rubble system are calibrated by means of ∼150 galaxies which have the best determined distance moduli μw0(Λc) and μw0(VM) previously derived from tertiary indicators (B0T, D0) via the corrected luminosity index Λc and from the 21 cm line widths via revised versions of the Tully-Fisher relations. The logarithm of the linear diameter Dr is shown to be a linear function of the family (F) and stage (T) parameters, and of the corrected luminosity class (Lc), if available. Two- and three- parameter calibration formulae are derived, and the zero point, i.e., the linear diameter of the ring in an average galaxy of type SAB(r)bc II (F=0, T=4, Lc=3), is determined to be r> ≍ 4.1 kpc. Possible dependences of the zero point on variety (r vs. rs), axis ratio (i.e. inclination), and redshift (i.e., distance) are investigated and found to be negligible in the distance modulus interval 29 < μ0 < 34. The calibration is extended to early-type spirals and lenticulars (-2 ≤ T < 2) by means of ∼50 objects which are probable members of groups including spirals whose distance moduli are known from radio or optical indicators. Formulae for the derivation of distance moduli from apparent diameters of rings reduced to standard values of F, T (and, where available, Lc for T ≥ 2) are given. The accidental mean errors of the distance moduli so derived are expected to be σ(μr0) ≍ 0.6 mag (three-parameter formula) and 0.7 mag (two-parameter formula) in well-observed cases, somewhat poorer than the tertiary indicators, but still useful, particularly in view of the potential range of applicability (Δ ≤ 100 Mpc). The zero point of the ring distance scale is consistent with the basic zero point defined by the primary and secondary indicators within the internal m.e. of 0.2 mag or better, and has an external mean error from all sources of ∼0.25 mag. In an appendix the ring diameters in our catalog are compared to those recently published by Kormendy and by Pedreros and Madore; all three sets are in excellent systematic agreement (with a few exceptions), and their external mean errors are calculated. The distances of several hundred ringed galaxies derived from all available measurements and the present calibration will be reported in Paper III. Publication: The Astrophysical Journal Supplement Series Pub Date: February 1982 DOI: 10.1086/190776 Bibcode: 1982ApJS...48..219B Keywords: Calibrating; Distance; Galactic Structure; Ring Structures; Spiral Galaxies; Diameters; Galactic Evolution; Least Squares Method; Luminosity; Statistical Analysis; Astronomy full text sources ADS | data products NED (82) Related Materials (4) Part 1: 1980ApJS...44..451D Part 3: 1983ApJS...51..149B Part 4: 1983ApJ...266....1B Part 5: 1983ApJ...272..380B