J/A+A/675/A143 NGC1277 + NGC1278 spectra + kinematic information (Comeron+ 2023)
The massive relic galaxy NGC 1277 is dark matter deficient. From dynamical
models of integral-field stellar kinematics out to five effective radii.
Comeron S., Trujillo I., Cappellari M., Buitrago F., Garduno L.E.,
Zaragoza-Cardiel J., Zinchenko I.A., Lara-Lopez M.A., Ferre-Mateu A.,
Dib S.
<Astron. Astrophys. 675, A143 (2023)>
=2023A&A...675A.143C 2023A&A...675A.143C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, optical ; Galaxies, spectra ; Models
Keywords: galaxies: elliptical and lenticular, cD - galaxies: evolution -
galaxies: formation - galaxies: individual: NGC 1277 -
galaxies: individual: NGC 1278 - galaxies: kinematics and dynamics
Abstract:
According to the Lambda cold dark matter cosmology (Lambda-CDM),
present-day galaxies with stellar masses Mstar>1011M☉ should
contain a sizable fraction of dark matter within their stellar body.
Models indicate that in massive early-type galaxies (ETGs) with
Mstar∼1.5x1011M☉, dark matter should account for ∼15% of the
dynamical mass within one effective radius (1Re) and for ∼60% within
5Re. Most massive ETGs have been shaped through a two-phase process:
the rapid growth of a compact core was followed by the accretion of an
extended envelope through mergers. The exceedingly rare galaxies that
have avoided the second phase, the so-called relic galaxies, are
thought to be the frozen remains of the massive ETG population at z>2.
The best relic galaxy candidate discovered to date is NGC 1277, in the
Perseus cluster. We used deep integral field George and Cynthia
Mitchel Spectrograph (GCMS) data to revisit NGC 1277 out to an
unprecedented radius of 6kpc (corresponding to 5Re). By using Jeans
anisotropic modelling, we find a negligible dark matter fraction
within 5Re (fDM(5Re)<0.05; two-sigma confidence level), which is in
tension with the Lambda-CDM expectation. Since the lack of an extended
envelope would reduce dynamical friction and prevent the accretion of
an envelope, we propose that NGC 1277 lost its dark matter very early
or that it was dark matter deficient ab initio. We discuss our
discovery in the framework of recent proposals, suggesting that some
relic galaxies may result from dark matter stripping as they fell in
and interacted within galaxy clusters. Alternatively, NGC 1277 might
have been born in a high-velocity collision of gas-rich proto-galactic
fragments, where dark matter left behind a disc of dissipative
baryons. We speculate that the relative velocities of ∼2000km/s
required for the latter process to happen were possible in the
progenitors of the present-day rich galaxy clusters.
Description:
Tables ngc1277.dat and ngc1278.dat contain the information required to
reconstruct the kinematic maps of NGC 1277 and NGC 1278, respectively.
The file spectra.fits contains the information regarding the reduced
spectra in four extensions. The first one contains the spectra for the
738 fibres, and the second one contains estimated errors (not used in
the article, since we derived them using the der_snr software). The
third extension contains the x positions in arcseconds and the fourth
extension contains the y positions in arcseconds. The centre of the
coordinates is arbitrary. In the system of coordinates of
spectra.fits, we estimate the centre of NGC 1277 to be found at
x=5.43arcsec and y=17.98arcsec. The centre of NGC 1278 is at
x=-23.97arcsec and y=-19.38arcsec. The coordinates in NGC1277.dat and
NGC1278.dat are set with respect to those centres.
Objects:
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RA (2000) DE Designation(s)
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03 19 51.48 +41 34 24.9 NGC 1277 = LEDA 12434
03 19 54.13 +41 33 48.2 NGC 1278 = LEDA 12438
--------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ngc1277.dat 36 47 Table required to reconstruct the kinematic
maps of NGC 1277
ngc1278.dat 36 183 Table required to reconstruct the kinematic
maps of NGC 1278
list.dat 89 1 Information of spectra.fits file
fits/* . 1 spectra.fits file
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Byte-by-byte Description of file: ngc1277.dat ngc1278.dat
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Bytes Format Units Label Explanations
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1- 6 F6.2 arcsec x X coordinate of the centre of the fibre with
respect to the centre of the galaxy
8- 13 F6.2 arcsec y Y coordinate of the centre of the fibre
with respect to the centre of the galaxy
15- 20 F6.1 km/s V Velocity corrected for a peculiar velocity of
5097km/s for NGC1277 and 6072km/s for NGC1278
22- 25 F4.1 km/s e_V Error in the velocity
27- 31 F5.1 km/s Sigma Velocity dispersion
33- 36 F4.1 km/s e_Sigma Error in the velocity dispersion
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Nx Number of pixels along X-axis
6- 8 I3 --- Ny Number of pixels along Y-axis
10- 19 A10 "datime" Obs.date Observation date
21- 27 F7.2 0.1nm blambda Lower value of wavelength interval
29- 35 F7.2 0.1nm Blambda Upper value of wavelength interval
37- 43 F7.5 0.1nm dlambda Wavelenght resolution
45- 49 I5 Kibyte size Size of FITS file
51- 62 A12 --- FileName Name of FITS file, in subdirectory fits
64- 89 A26 --- Title Title of the FITS file
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Acknowledgements:
Sebastien Comeron, lsebasti(at)ull.edu.es
(End) S. Comeron [Univ. de La Laguna, Spain], P. Vannier [CDS] 08-Jun-2023