The Slug Nebula is one of the largest and most luminous Lyman-a (Ly α) nebulae discovered to date, extending over 450 kpc around the bright quasar UM287 at z= 2.283. Characterized by high surface brightnesses over intergalactic scales, its Ly α emission may either trace high-density ionized gas ('clumps') or large column densities of neutral material. To distinguish between these two possibilities, information from a non-resonant line such as Hα is crucial. Therefore, we analysed a deep Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE) observation of one of the brightest Ly α-emitting regions in the Slug Nebula with the goal of detecting associated Hα emission. We also obtained a deep, moderate resolution Ly α spectrum of the nearby brightest region of the Slug. We detected an Hα flux of FHα = 2.62 ± 0.47 × 10-17 erg cm-2 s-1 (SBHα = 2.70 ± 0.48 × 10-18 erg cm-2 s-1 arcsec-2 at the expected spatial and spectral location. Combining the Hα detection with its corresponding Ly α flux (determined from the narrow-band imaging), we calculate a flux ratio of FLyα/FHα = 5.5 ± 1.1. The presence of a skyline at the location of the Hα emission decreases the signal-to-noise ratio of the detection and our ability to put stringent constraints on the Hα kinematics. Our measurements argue for the origin of the Ly α emission being recombination radiation, suggesting the presence of high-density ionized gas. Finally, our high-resolution spectroscopic study of the Ly α emission does not show evidence of a rotating disc pattern and suggest a more complex origin for at least some parts of the Slug Nebula.

Leibler, C., Cantalupo, S., Holden, B., Madau, P. (2018). The detection of intergalactic Hα emission from the Slug Nebula at z ~ 2.3. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 480(2), 2094-2108 [10.1093/MNRAS/STY1764].

The detection of intergalactic Hα emission from the Slug Nebula at z ~ 2.3

Cantalupo S.
;
2018

Abstract

The Slug Nebula is one of the largest and most luminous Lyman-a (Ly α) nebulae discovered to date, extending over 450 kpc around the bright quasar UM287 at z= 2.283. Characterized by high surface brightnesses over intergalactic scales, its Ly α emission may either trace high-density ionized gas ('clumps') or large column densities of neutral material. To distinguish between these two possibilities, information from a non-resonant line such as Hα is crucial. Therefore, we analysed a deep Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE) observation of one of the brightest Ly α-emitting regions in the Slug Nebula with the goal of detecting associated Hα emission. We also obtained a deep, moderate resolution Ly α spectrum of the nearby brightest region of the Slug. We detected an Hα flux of FHα = 2.62 ± 0.47 × 10-17 erg cm-2 s-1 (SBHα = 2.70 ± 0.48 × 10-18 erg cm-2 s-1 arcsec-2 at the expected spatial and spectral location. Combining the Hα detection with its corresponding Ly α flux (determined from the narrow-band imaging), we calculate a flux ratio of FLyα/FHα = 5.5 ± 1.1. The presence of a skyline at the location of the Hα emission decreases the signal-to-noise ratio of the detection and our ability to put stringent constraints on the Hα kinematics. Our measurements argue for the origin of the Ly α emission being recombination radiation, suggesting the presence of high-density ionized gas. Finally, our high-resolution spectroscopic study of the Ly α emission does not show evidence of a rotating disc pattern and suggest a more complex origin for at least some parts of the Slug Nebula.
Articolo in rivista - Articolo scientifico
Cosmology: observations; Galaxies: haloes; Galaxies: high-redshift; Intergalactic medium; Quasars: emission lines;
English
2094
2108
15
Leibler, C., Cantalupo, S., Holden, B., Madau, P. (2018). The detection of intergalactic Hα emission from the Slug Nebula at z ~ 2.3. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 480(2), 2094-2108 [10.1093/MNRAS/STY1764].
Leibler, C; Cantalupo, S; Holden, B; Madau, P
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/372589
Citazioni
  • Scopus 13
  • ???jsp.display-item.citation.isi??? 14
Social impact