A deep Chandra study confirms diffuse nonthermal X-ray emission from the globular cluster Terzan 5

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Table 3

Spectral fits of the inner three rings.

No. Ring	Model: (TBABS×PL)_LXB+(TBABS×PL)_Ter5
	N_H,LXB^(a)	Γ_Ter5	F_surf,Ter5 ^(b)	$d . o . f . / χ_{ν}^{2}$ ${\rm{d}}{\rm{.o}}{\rm{.f}}{\rm{.}}/\chi _v^2$
1	0.27 ± 0.05	1.96 ± 0.18	9.73 ± 0.50	240/1.02
2	0.33 ± 0.05	3.21 ± 0.33	6.41 ± 1.40	285/1.07
3	0.22 ± 0.04	3.48 ± 0.71	3.24 ± 1.63	284/1.07

	Model: (TBABS×PL)_LXB+(TBABS×BREM)_Ter5
No. Ring	N_H,LXB^(a)	kT_Ter5^(c)	Norm^(d)	F_surf,Ter5 (b)	$d . o . f . / χ_{ν}^{2}$ ${\rm{d}}{\rm{.o}}{\rm{.f}}{\rm{.}}/\chi _v^2$

1	0.26 ± 0.04	3.11 ± 0.83	4.84 ± 0.63	8.29 ± 1.62	240/1.02
2	0.31 ± 0.04	0.99 ± 0.19	9.89 ± 3.16	4.07 ± 1.68	285/1.06
3	0.21 ± 0.04	0.86 ± 0.31	6.94 ± 4.71	1.70 ± 1.33	284/1.06

Notes. LXB and Ter5 denote the diffuse X-ray components from the local X-ray background and Terzan 5, respectively. Errors are quoted at 1 sigma. ^(a)Hydrogen column density in units of 10²² cm^–2. ^(b)Unabsorbed X-ray surface flux in the band 0.5–6 keV in units of 10^–18 erg cm^–2 s^–1 arcsec^–2. ^(c)The plasma temperature in keV. ^(d)The normalization of the BREM model in units of 10^–5 cm^–5, given by 3.02 × 10^–15 ∫n_en_IdV/4πD², where D is the distance to the source in cm and n_e, n_I are the electron and ion densities in cm^–3.

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