Resonant line transfer in a fog: using Lyman-alpha to probe tiny structures in atomic gas

Max Gronke; Mark Dijkstra; Michael McCourt; S. Peng Oh

doi:10.1051/0004-6361/201731013

Home

All issues

Volume 607 (November 2017)

A&A, 607 (2017) A71

Full HTML

Free Access

Table 1

Summary of the regimes found in a static, clumpy medium.

Name	Requirement^a	N_cl^b	x_p^c	Description

Free-streaming	τ_0,total ≲ 1	∝ f_c	~ 0	Photons stream through clumps
Porous	(τ_0,total ≳ 1) ∧ (f_c ≲ 1)	~ 0	~ 0	Escape through holes without interaction
Random-walk		∝ f_c²	~ 0	Scatter off clumps until escape
Homogeneous {		∝ f_c	~ x_esc ^A	Excursion-like escape
Homogeneous {		∝ f_c	~ x_∗ ^B	Escape in a single flight

Notes. The regimes are described in detail in Sect. 2.3.

^(a)

Parameter space of regime. Visualized in Fig. 1.

^(b)

Average number of clumps a photon encounters before escape.

^(c)

Dominant frequency of escape.

^(A)

Escape frequency from a homogeneous slab (Eq. (5)).

^(B)

Boundary between core and wing of the line. x_∗ ~ 3.26 for T = 10⁴K.

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.