6C B140400.6+405554
Elliptical radio galaxy in Canes Venatici with active nucleus.
6C B140400.6+405554 (also cataloged as OGC 642 and J140604.1+404140) is a radio galaxy in the constellation Canes Venatici. It is an elliptical galaxy and the brightest member of the WHL J140604.0+404139 galaxy cluster, which contains 20 confirmed member candidates. Astronomers first identified it in 1988 during the Sixth Cambridge Survey of Radio Sources.
The galaxy has a redshift of 0.210. Its R-band magnitude is 16.68, with an absolute magnitude of -23.54. At its center lies a supermassive black hole with a mass estimated at 8.77 M☉, though some studies suggest 8.76 M☉. The active nucleus has been classified in multiple ways: as a Fanaroff-Riley Class Type I radio galaxy, a bend-tail X-shaped radio galaxy with a Fanaroff-Riley Class Type II-like source, and a narrow-angle-tail (NAT) radio galaxy. One study also describes it as a C-shaped radio galaxy.
The radio lobes are resolved and span a maximum size of 84.28 kiloparsecs. The total log radio luminosity is 26.07 W Hz⁻¹, while another measurement at 1.4 GHz gives 25.58 W Hz⁻¹. Detected radio jets have an opening angle of 64.3° and a curvature radius of 16.2 arcseconds. The source has a largest angular size of 48 arcseconds and a largest linear size of 171.0 kiloparsecs, with a total extent of 0.13 megaparsecs. The NRAO VLA Sky Survey (NVSS) measures a radio flux density of 261.00 mJy at 1.4 GHz, and the radio spectral index is 0.98α.
The optical spectrum shows hydrogen-alpha and doubly ionized oxygen emission lines, with line luminosities of 7.367 L☉ and 7.018 L☉, respectively.
- Redshift
- 0.210
- R-band magnitude
- 16.68
- Absolute magnitude
- -23.54
- Supermassive black hole mass
- 8.77 M☉ (suggested 8.76 M☉)
- Largest linear size
- 171.0 kiloparsecs
- Radio flux density (nvss)
- 261.00 mJy at 1.4 GHz
- Radio spectral index
- 0.98α
Lore & Background
6C B140400.6+405554 is an elliptical galaxy with an active nucleus, classified as either a Fanaroff-Riley Class Type I radio galaxy or a bend-tail X-shaped radio galaxy with a Fanaroff-Riley Class Type II-like source. It has also been classified as a narrow-angle-tail (NAT) radio galaxy and, in a separate study, as a C-shaped radio galaxy. Both of its radio lobes are resolved, reaching a maximum size of 84.28 kiloparsecs, and the total log radio luminosity is 26.07 W Hz−1. The radio jets have an opening angle of 64.3° and a curvature radius of 16.2 arcseconds. The largest angular size of the source is 48 arcseconds, and the largest linear size is 171.0 kiloparsecs. The optical spectrum shows hydrogen-alpha and doubly ionized oxygen emission lines with luminosities of 7.367 and 7.018 L☉, respectively.
Reader's Guide
6C B140400.6+405554 is notable as a radio galaxy with multiple morphological classifications, reflecting the complexity of its radio structure. Its status as the brightest cluster galaxy of the WHL J140604.0+404139 cluster underscores its role in that environment. The galaxy's supermassive black hole mass is estimated at 8.77 M☉, with a suggested alternative of 8.76 M☉, indicating some uncertainty. The radio source exhibits both resolved lobes and jets, with a total extent of 0.13 megaparsecs. The presence of hydrogen-alpha and doubly ionized oxygen emission lines in its optical spectrum confirms ongoing nuclear activity. The galaxy's discovery in the Sixth Cambridge Survey of Radio Sources in 1988 places it within a well-known catalog of radio sources. Its varied classifications—Fanaroff-Riley Type I, bend-tail X-shaped, narrow-angle-tail, and C-shaped—highlight the challenges in categorizing such sources and contribute to the understanding of radio galaxy morphology and evolution.
Did You Know?
- The galaxy has a supermassive black hole mass of 8.77 M☉, though 8.76 M☉ has also been suggested.
- It is classified as both a Fanaroff-Riley Class Type I and a bend-tail X-shaped radio galaxy.
- The radio lobes reach a maximum size of 84.28 kiloparsecs.
Frequently Asked Questions
What is 6C B140400.6+405554?
It is an elliptical radio galaxy with an active nucleus, also cataloged under the designations OGC 642 and J140604.1+404140. It sits in the constellation Canes Venatici and serves as the brightest confirmed member of the WHL J140604.0+404139 cluster, which holds twenty member candidates.
How was 6C B140400.6+405554 first identified?
Astronomers detected it in 1988 as part of the Sixth Cambridge Survey of Radio Sources. Its strong radio emission at 1.4 GHz, measured at roughly 261 mJy in the NVSS catalog, is what made it stand out during that survey.
What is at the center of 6C B140400.6+405554?
The galaxy hosts an active galactic nucleus powered by a supermassive black hole, with mass estimates clustering around 8.77 solar masses (some analyses give 8.76). This active core is the source of the galaxy's characteristic radio luminosity.
How large is 6C B140400.6+405554 and how bright does it appear?
Its largest linear extent stretches to about 171 kiloparsecs, and its intrinsic brightness is reflected in an absolute R-band magnitude of −23.54. From Earth it registers at an R-band apparent magnitude of 16.68, placing it well beyond naked-eye visibility.
Why do astronomers consider 6C B140400.6+405554 important for studying galaxy clusters?
As the dominant elliptical member of a twenty-galaxy cluster, it provides a benchmark for understanding how supermassive black holes and radio emission evolve in dense group environments. Its redshift of 0.210 also anchors the distance scale for the entire WHL J140604.0+404139 system.
More in Elliptical and Irregular Galaxies, Part 2 1-24
Spotted an error? Know more?
Reader corrections go straight into our review queue. Suggest an edit · How this site is sourced