The far-infrared morphology of the double-ringed galaxy NGC 4736 (M94) - A ring surrounding an extended nucleus

Journal Article · Wed May 01 00:00:00 EDT 1991 · Astrophysical Journal; (United States)

DOI:https://doi.org/10.1086/170023· OSTI ID:5549317

Smith, B J; Lester, D F; Harvey, P M; Pogge, R W ^[1]

---

1. Texas, University, Austin Ohio State University, Columbus (USA)

High spatial resolution 100-micron observations of the central region of the double-ringed spiral galaxy NGC 4736 (M94) were obtained using the Kuiper Airborne Observatory. The data show a strong central peak with secondary peaks at the radius of the inner ring (50 arcsec = 1.6 kpc). The nuclear emission is extended at 100 microns, with a radius of 15 arcsec (500 pc). The far-infrared morphology is similar to that of the molecular gas, while the H I distribution shows a pronounced central depression. Since most of the hydrogen gas in the inner regions of NGC 4736 is in molecular form, it is concluded that the far-infrared emission from NGC 4736 arises mainly from dust associated with molecular gas. The H-alpha distribution differs dramatically from the far-infrared and molecular gas distributions. The ring dominates the H-alpha emission, while the total 100-micron ring emission is only slightly larger than that of the nucleus, yielding an L(FIR)/L(H-alpha) for the nucleus about 100 times that of the ring. The bolometric luminosity of the stars in the inner 1 kpc of NGC 4736 is sufficient to power the far-infrared from this region, which suggests that a significant fraction of the far-infrared emission in the nuclear region of NGC 4736 is powered by non-OB stars rather than by star formation. 61 refs.

• Research Organization: Texas Univ., Austin, TX (United States)
• OSTI ID: 5549317
• Journal Information: Astrophysical Journal; (United States), Vol. 373; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
GALAXIES
FAR INFRARED RADIATION
MORPHOLOGY
COSMIC DUST
COSMIC GASES
GALAXY NUCLEI
INFRARED SPECTRA
INTERSTELLAR SPACE
RESOLUTION
SPATIAL DISTRIBUTION
SPATIAL RESOLUTION
SPIRAL CONFIGURATION
VISIBLE SPECTRA
CONFIGURATION
DISTRIBUTION
DUSTS
ELECTROMAGNETIC RADIATION
FLUIDS
GASES
INFRARED RADIATION
RADIATIONS
SPACE
SPECTRA
640105* - Astrophysics & Cosmology- Galaxies