Spiral DRAGNs or Speca-like galaxies are a type of spiral galaxies which are also radio galaxies or which contain DRAGNs (Double Radio-source Associated with Galactic Nucleus).
Most DRAGNs are associated with elliptical galaxies, as are most double-lobed radio-galaxies. [1] Spiral DRAGNs are inconsistent with currently known galaxy formation processes. [2] As of 2024, there are nearly 36 spiral DRAGNs. [3]
Lenticlular galaxies containing DRAGNs are as rare as spiral DRAGNs, with only 5 known examples as of 2020, [4] including: Centaurus A, [5] [6] NGC 612 [7] and NGC 1534. [4] Nearby Seyfert galaxies containing small or galaxy-scale radio jets/lobes are not accepted as Specas or Spiral DRANGs.
Galaxy | Identified Date | Notes | References |
---|---|---|---|
galaxy 0313-192 | 1998 | First known spiral DRAGN, located in Abell 428. It is the first spiral DRAGN with VLBI detection. [8] | [9] [10] [11] |
Speca | 2011 | First confirmed case due to its episodic radio jet nature. Hosted in a massive spiral and with giant Mpc-scale radio-lobes. It was the second galaxy shown to have three episodes of periodic activity, the first was an elliptical. [NB 1] | [12] [13] [10] |
J2345-0449 | 2014 | Third known spiral DRAGN with two episodic activities, observed at radio wavelengths and measuring about 1.6 megaparsecs in total size. | [14] |
SDSS J1649+2635 | 2014 | Fourth known spiral DRAGN; first located in a grand design spiral galaxy. It was discovered by cross-matching spiral galaxies identified by galaxy zoo volunteers with the Unified Radio Catalog. It was the first systematic search for spiral DRAGNs. | [1] [15] [10] [16] |
J0836+0532 | 2015 | Two clear spiral arms | [17] |
J1159+5820 | 2012/2015 | Candidate: Disturbed galaxy with signs of a merger. | [18] [17] |
J1352+3126 | 2015 | Candidate: Galaxy was well studied at the time of the discovery by Singh et al. The galaxy was classified as spiral or irregular galaxy. | [17] |
MCG+07-47-10 | 2016 | radio source has a low luminosity | [19] |
J0354-1340 | 2022 | spiral host that is a narrow-line Seyfert 1, size of the de-projected jets is 250 kpc | [20] |
J0209+0750 | 2022 | loose spiral arms, has star-forming clumps | [21] |
J0806+0624 | 2022 | several spiral arms and a luminous bar-like feature | [21] |
J1328+5710 | 2022 | low-mass, low-redshift galaxy with many star-forming regions, at least two prominent arms and a strong bar. One of the few intermediate massive black holes (≤ 105 M☉) with a strong radio emission and the first with a double-lobed radio emission. | [21] |
J1656+6407 | 2022 | extremely massive star-forming spiral galaxy | [21] |
J1128+2417 | 2022 | star-forming clumps in the arms | [21] |
J1646+383 | 2022 | dust-lane with peculiar arc-like shape | [21] |
J0326-0623 | 2023 | two major spiral arms, scale of the radio lobes is 430 kpc | [3] |
J1110+0321 | 2023 | scale of the radio lobes is 100 kpc | [3] |
J1134+3046 | 2023 | scale of the radio lobes is 380 kpc | [3] |
NGC 1427 is a low-luminosity elliptical galaxy located approximately 71 million light-years away from Earth. It was discovered by John Frederick William Herschel on November 28, 1837. It is a member of the Fornax Cluster. The galaxy has a stellar mass of 7.9 × 1010M☉, and a total mass of 9.4 × 1010M☉. However, the mass of the dark matter halo surrounding the galaxy is around 4.3 × 1012M☉.
NGC 1042 is a spiral galaxy located in the constellation Cetus. It was discovered on 10 November 1885 by American astronomer Lewis Swift. The galaxy has an apparent magnitude of 14.0.
NGC 4323 is a lenticular or dwarf elliptical galaxy located about 52.5 million light-years away in the constellation Coma Berenices. The galaxy was discovered in 1882 by astronomer Wilhelm Tempel and is a member of the Virgo Cluster.
NGC 3862 is an elliptical galaxy located 300 million light-years away in the constellation Leo. Discovered by astronomer William Herschel on April 27, 1785, NGC 3862 is an outlying member of the Leo Cluster.
NGC 3311 is a super-giant elliptical galaxy located about 190 million light-years away in the constellation Hydra. The galaxy was discovered by astronomer John Herschel on March 30, 1835. NGC 3311 is the brightest member of the Hydra Cluster and forms a pair with NGC 3309 which along with NGC 3311, dominate the central region of the Hydra Cluster.
NGC 708 is an elliptical galaxy located 240 million light-years away in the constellation Andromeda and was discovered by astronomer William Herschel on September 21, 1786. It is classified as a cD galaxy and is the brightest member of Abell 262. NGC 708 is a weak FR I radio galaxy and is also classified as a type 2 Seyfert galaxy.
NGC 753 is a spiral galaxy located 220 million light-years away in the constellation Andromeda. The galaxy was discovered by astronomer by Heinrich d'Arrest on September 16, 1865 and is a member of Abell 262.
NGC 759 is an elliptical galaxy located 230 million light-years away in the constellation Andromeda. NGC 759 was discovered by astronomer by Heinrich d'Arrest on September 17, 1865. It is a member of Abell 262.
NGC 4061 is an elliptical galaxy located 310 light-years away in the constellation Coma Berenices. It was discovered by astronomer William Herschel on April 27, 1785. It was rediscovered by John Herschel on April 29, 1832. It is listed both as NGC 4061 and NGC 4055. NGC 4061 is a member of the NGC 4065 Group and forms an interacting pair with its companion, NGC 4065 as evidenced by distortions in their optical isophotes.
NGC 4093 is an elliptical galaxy located 340 million light-years away in the constellation Coma Berenices. The galaxy was discovered by astronomer Heinrich d'Arrest on May 4, 1864. NGC 4093 is a member of the NGC 4065 Group and is a radio galaxy with a two sided jet.
The NGC 4065 Group is a group of galaxies located about 330 Mly (100 Mpc) in the constellation Coma Berenices. The group's brightest member is NGC 4065 and located in the Coma Supercluster.
NGC 4294 is a barred spiral galaxy with flocculent spiral arms located about 55 million light-years away in the constellation Virgo. The galaxy was discovered by astronomer William Herschel on March 15, 1784 and is a member of the Virgo Cluster.
NGC 4298 is a flocculent spiral galaxy located about 53 million light-years away in the constellation Coma Berenices. The galaxy was discovered by astronomer William Herschel on April 8, 1784 and is a member of the Virgo Cluster.
NGC 4299 is a featureless spiral galaxy located about 55 million light-years away in the constellation Virgo. It was discovered by astronomer William Herschel on March 15, 1784 and is a member of the Virgo Cluster.
NGC 4302 is an edge-on spiral galaxy located about 55 million light-years away in the constellation Coma Berenices. It was discovered by astronomer William Herschel on April 8, 1784 and is a member of the Virgo Cluster.
NGC 4324 is a lenticular galaxy located about 85 million light-years away in the constellation Virgo. It was discovered by astronomer Heinrich d'Arrest on March 4, 1862. NGC 4324 has a stellar mass of 5.62 × 1010M☉, and a baryonic mass of 5.88 × 1010M☉. The galaxy's total mass is around 5.25 × 1011M☉. NGC 4324 is notable for having a ring of star formation surrounding its nucleus. It was considered a member of the Virgo II Groups until 1999, when its distance was recalculated and it was placed in the Virgo W Group.
An extended emission-line region (EELR) is a giant interstellar cloud ionized by the radiation of an active galactic nucleus (AGN) inside a galaxy or photons produced by the shocks associated with the radio jets. An EELR can appear as a resolved cloud in relative nearby galaxies and as narrow emission lines in more distant galaxies.
J2345-0449 or 2MASX J23453268-0449256, is a spiral galaxy located 947 million light-years in the constellation of Aquarius. It contains an active galactic nucleus and is classified as a radio galaxy, containing relativistic jets that are projected out from its spiral host by ~1.6 Mpc, making these jets the largest and rarest known. It was discovered in 2014 by amateur astronomers, making it the third spiral DRAGN after ESO 0313-192 and Speca.
Abell 1942 BCG, also known as PGC 1256558, is a massive elliptical galaxy of type-cD residing as the brightest cluster galaxy of the Abell 1942 galaxy cluster, located in the constellation Virgo. With a redshift of 0.224, the galaxy is located nearly 2.7 billion light-years away from Earth.
PKS 2004-447 is a narrow-line Seyfert 1 galaxy located in the constellation of Sagittarius. It has a redshift of (z) 0.24 and is the radio-loudest gamma ray emitting AGN known in the southern hemisphere. It was first identified as an astronomical radio source during a very-long-baseline interferometry survey in 1989. The radio spectrum appears to be powerful and compact, making it a compact steep spectrum source. The X-ray emission for this source is described by a simple power-law in the energy range.
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