TGSS J1530+1049
| TGSS J1530+1049 | |
|---|---|
Here is a two dimensional spectrum with a strong emission line from GMOS of TGSS J1530+1049. | |
| Observation data | |
| Constellation | Serpens |
| Right ascension | 15h 30m 49.44s |
| Declination | +10° 49′ 20.0″ |
| Redshift | 5.72 |
| Distance | 12.5 billion light years (light travel distance) |
| Characteristics | |
| Type | High redshift radio galaxy |
| Mass | 10^10.5 solar mass M☉ |
| Notable features | Most distant radio galaxy discovered to date |
TGSS J1530+1049 was the most distant radio galaxy, discovered at a redshift distance of z=5.72 placing it close to the epoch of reionization[1] and classifying it has a high redshift radio galaxy (HzRG). The galaxy has a size of 3.5 kiloparsecs, comparable to radio galaxies at z>4 and has a luminosity of 5.7x10^42 ergs, making it comparable in luminosity to non-radio galaxies located at similar redshift distances.[2] In 2023, it was discovered in the LOFAR Two-Metre Sky Survey that a radio galaxy named ILT J2336+1842 was more distant at redshift z = 6.6.[3] However, another radio galaxy named GLEAM J0917-0012 may be farther but its distance is undetermined (likely z=7).[4]
TGSS J1530+1049 is likely early in its phase of evolution and still assembling which was determined due to its relatively low stellar mass compared to other radio galaxies (10^10.5 solar masses).[2] The radio emission is powered by a supermassive black hole (SMBH) consuming material from the surrounding environment. This galaxy's massive black hole provides evidence that black holes had grown very quickly to supermassive sizes in the early universe.[5]
High-resolution radio imaging and environment
Follow-up observations of TGSS J1530+1049 using the European VLBI Network (EVN) and the e-MERLIN interferometric array have revealed the detailed small-scale radio morphology of the galaxy at milliarcsecond to sub-arcsecond resolution. Despite appearing unresolved in previous radio surveys down to ~0.6 arcseconds, high-resolution imaging shows that the source consists of multiple steep-spectrum radio components aligned roughly north–south and separated by several kiloparsecs.[6]
At 1.7 GHz, EVN imaging resolves two compact features separated by about 2.8 kpc, each having high brightness temperatures (>107 K), confirming their origin in AGN-related synchrotron emission rather than star formation. e-MERLIN observations at 1.5 and 5 GHz detect a larger-scale pair of steep-spectrum components extending to a total projected size of roughly 5.5 kpc, placing TGSS J1530+1049 among medium-sized symmetric objects (MSOs)—compact, likely young radio galaxies that may be precursors to larger classical radio sources.
Notably, no flat-spectrum radio core is detected at the sensitivity of the observations, suggesting that the central AGN is either intrinsically faint at cm wavelengths or heavily obscured. The observed radio structures are instead interpreted as lobes or hotspots formed by compact jets interacting with the surrounding medium.
Recent imaging and spectroscopic data from the James Webb Space Telescope (JWST) have shown that TGSS J1530+1049 resides within a dense, merging environment at a revised redshift of z = 4.0, lower than the earlier estimate of z = 5.72. The galaxy is embedded in a complex system of multiple interacting galaxies and extended ionized gas. Maps of Hα emission from the JWST/NIRSpec IFU reveal bright, kinematically disturbed gas knots that are strongly aligned with the radio axis, extending over ~25 kpc—significantly larger than the radio source itself. This alignment suggests interactions between the compact radio jets and the surrounding gas, as well as possible contributions from ionization by an obscured active nucleus and nearby star-forming companions.
Together, the radio and JWST observations depict TGSS J1530+1049 as a young, compact radio galaxy in the early stages of assembly, embedded in one of the densest known environments at this epoch and hosting at least one actively accreting supermassive black hole.
See also
- ILT J2336+1842, current most distant radio galaxy.
- GLEAM J0917-0012, a potentially more distant radio galaxy.
References
- ^ "Astronomers discover most distant radio galaxy - UPI.com". UPI. Retrieved 2025-06-11.
- ^ a b Saxena, A; Marinello, M; Overzier, R A; Best, P N; Röttgering, H J A; Duncan, K J; Prandoni, I; Pentericci, L; Magliocchetti, M; Paris, D; Cusano, F; Marchi, F; Intema, H T; Miley, GK (2018-10-21). "Discovery of a radio galaxy at z = 5.72". Monthly Notices of the Royal Astronomical Society. 480 (2): 2733–2742. arXiv:1806.01191. Bibcode:2018MNRAS.480.2733S. doi:10.1093/mnras/sty1996. ISSN 0035-8711.
- ^ Hardcastle, M. J. (2023). "The LOFAR Two-Metre Sky Survey. VI. Optical identifications for the second data release". NASA ADS. Retrieved 2025-12-13.
- ^ Drouart, Guillaume; Seymour, Nick; Broderick, Jess W.; Afonso, José; Chhetri, Rajan; De Breuck, Carlos; Emonts, Bjorn; Galvin, Tim J.; Lehnert, Matthew D.; Morgan, John; Stern, Daniel; Vernet, Joël; Wright, Nigel (2021). "The nature and likely redshift of GLEAM J0917-0012". Publications of the Astronomical Society of Australia. 38 e049. arXiv:2111.08103. Bibcode:2021PASA...38...49D. doi:10.1017/pasa.2021.35.
- ^ info@noirlab.edu. "Gemini Confirms the Most Distant Radio Galaxy". www.noirlab.edu (in Spanish). Retrieved 2025-06-11.
- ^ "High-resolution radio imaging of TGSSJ1530+1049, a radio galaxy in a dense environment at z = 4".