Extremely strong CIV 1550 nebular emission in the extremely low-metallicity star-forming galaxy J2229+2725
In: MNRAS 528, L10 (2024); (2023)
Online
report
Using Hubble Space Telescope (HST)/Cosmic Origins Spectrograph (COS) observations of one of the most metal-poor dwarf star-forming galaxies (SFG) in the local Universe, J2229+2725, we have discovered an extremely strong nebular CIV 1549, 1551 emission-line doublet, with an equivalent width of 43A, several times higher than the value observed so far in low-redshift SFGs. Together with other extreme characteristics obtained from optical spectroscopy (oxygen abundance 12+log(O/H)=7.085+/-0.031, ratio O32 = I([OIII]5007)/I([OII]3727) ~ 53, and equivalent width of the Hbeta emission line EW(Hbeta) = 577A), this galaxy greatly increases the range of physical properties for dwarf SFGs at low redshift and is a likely analogue of the high-redshift dwarf SFGs responsible for the reionization of the Universe. We find the ionizing radiation in J2229+2725 to be stellar in origin and the high EW(CIV 1549,1551) to be due to both extreme ionization conditions and a high carbon abundance, with a corresponding log C/O = -0.38, that is ~ 0.4 dex higher than the average value for nearby low-metallicity SFGs.
Comment: 6 pages, 4 figures, accepted for publikation in Monthly Notices of the Royal Astronomical Society Letters
Titel: |
Extremely strong CIV 1550 nebular emission in the extremely low-metallicity star-forming galaxy J2229+2725
|
---|---|
Autor/in / Beteiligte Person: | Izotov, Y. I. ; Schaerer, D. ; Guseva, N. G. ; Thuan, T. X. ; Worseck, G. |
Link: | |
Quelle: | MNRAS 528, L10 (2024); (2023) |
Veröffentlichung: | 2023 |
Medientyp: | report |
DOI: | 10.1093/mnrasl/slad166 |
Schlagwort: |
|
Sonstiges: |
|