Disentangling the X-ray variability in the Lyman continuum emitter Haro 11

¹ Eureka Scientific, 2452 Delmer Street, Suite 100, Oakland, CA 94602-3017, USA
² Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), AP 51, 72000 Puebla, Mexico
³ Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune University Campus, Pune 411007, India
⁴ Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden

Received: 29 January 2024
Accepted: 19 June 2024

Abstract

Context. Lyman break analogs in the local Universe serve as counterparts to Lyman break galaxies (LBGs) at high redshifts, which are widely regarded as major contributors to cosmic reionization in the early stages of the Universe.

Aims. We studied XMM-Newton and Chandra observations of the nearby LBG analog Haro 11, which contains two X-ray-bright sources, X1 and X2. Both sources exhibit Lyman continuum (LyC) leakage, particularly X2.

Methods. We analyzed the X-ray variability using principal component analysis (PCA) and performed spectral modeling of the X1 and X2 observations made with the Chandra ACIS-S instrument.

Results. The PCA component, which contributes to the X-ray variability, is apparently associated with variable emission features, likely from ionized superwinds. Our spectral analysis of the Chandra data indicates that the fainter X-ray source, X2 (X-ray luminosity L_X ∼ 4 × 10⁴⁰ erg s⁻¹), the one with higher LyC leakage, has a much lower absorbing column (N_H ∼ 1.2 × 10²¹ cm⁻²) than the heavily absorbed luminous source X1 (L_X ∼ 9 × 10⁴⁰ erg s⁻¹ and N_H ∼ 11.5 × 10²¹ cm⁻²).

Conclusions. We conclude that X2 is likely less covered by absorbing material, which may be a result of powerful superwinds clearing galactic channels and facilitating the escape of LyC radiation. Much deeper X-ray observations are required to validate the presence of potential superwinds and determine their implications for the LyC escape.