2 Micron spectroscopy of the nucleus of NGC 1068

Journal Article · Tue Sep 15 04:00:00 EDT 1981 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/159220· OSTI ID:5625433

Hall, D N.B.; Kleinmann, S G; Scoville, N Z; Ridgway, S T

A 2.0-2.4 ..mu..m spectrum taken at a resolution of 5 cm/sup -1/ (350 km s/sup -1/) with a small aperture (3''.8) centered on the nucleus of NGC 1068 exhibits both stellar and interstellar features. Stars are evident from the presence of first overtone CO absorption bands, the strengths of which suggest that late-type giant stars contribute about 25% of the 2.3 ..mu..m continuum within 2 '' (200 pc) of the galactic center. The estimated velocity dispersion of the stars is < or approx. =200 km s/sup -1/. Subtraction of this starlight from the spectrum leaves a gray body continuum component characterized by Tapprox.800 K. The K band flux distribution of this nonstellar emission suggests an identification with the compact source dominant at lambda> or approx. =3 ..mu..m and is inconsistent with extrapolation of the ..nu../sup -1.85/ power law ultraviolet source. Measured Brackett ..gamma.. (n = 7..-->..4) and quadrupole H/sub 2/ emission line fluxes are in agreement with previous, larger aperture measurements, implying that both the atomic and molecular emissions are predominantly confined to within 200 pc of the nucleus. The observed H/sub 2/ lines are much narrower than atomic emission lines, exhibiting widths similar to those of stellar absorption features. We argue that the H/sub 2/ lines are formed in molecular clouds whose kinematics are determined by the gravitational potential of the nucleus. Comparison of infrared luminosity, B2lt. slash luminosity, total H/sub 2/ line luminosity, and cloud mass supports the hypothesis that the infrared luminosity of NGC 1068 is determined by the level of star formation activity.

• Research Organization: Kitt Peak National Observatory
• OSTI ID: 5625433
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 248:3; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics &amp; Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
EMISSION SPECTRA
GALAXIES
GALAXY NUCLEI
GIANT STARS
INFRARED SPECTRA
LINE WIDTHS
LUMINOSITY
MASS
NEBULAE
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATION FLUX
SEYFERT GALAXIES
SPECTRA
SPECTROSCOPY
STARS