J/MNRAS/415/2417 ASK spectroscopic sequence of galaxies (Ascasibar+, 2011)
Do galaxies form a spectroscopic sequence?
Ascasibar Y., Sanchez Almeida J.
<Mon. Not. R. Astron. Soc., 415, 2417-2425 (2011)>
=2011MNRAS.415.2417A 2011MNRAS.415.2417A
ADC_Keywords: Models ; Spectroscopy
Keywords: methods: data analysis - methods: statistical -
galaxies: fundamental parameters
Abstract:
We identify a spectroscopic sequence of galaxies, analogous to the
Hubble sequence of morphological types, based on the Automatic
Spectroscopic K-means-based (ASK) classification. Considering galaxy
spectra as multidimensional vectors, the majority of the spectral
classes are distributed along a well-defined curve going from the
earliest to the latest types, suggesting that the optical spectra of
normal galaxies can be described in terms of a single affine
parameter. Optically bright active galaxies, however, appear as an
independent, roughly orthogonal branch that intersects the main
sequence exactly at the transition between early and late types.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 42 3850 *Template spectrum of ASK class 5 and basis vectors
ΔT and ΔA as a function of wavelength
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Note on table1.dat: Automatic Spectroscopic K-means-based classification (ASK)
of the class 5 typical of the "green valley" between early- and late-
type galaxies, temporarily found in an active state
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 F7.2 0.1nm lambda Wavelength
10- 18 E9.4 --- C5 Spectral template of class 5
20- 29 E10.5 --- DeltaT Basis vector ΔT
31- 40 E10.5 --- DeltaA Basis vector ΔA
42 I1 --- Mask [0/1] Binary flag indicating whether that
particular wavelength is included in the
bands used to define the ASK classes
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 20-Mar-2012