Redshifted X-rays from the material accreting onto TW Hydrae: Evidence of a low-latitude accretion spot

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Table 4

Spectral model parameter estimation for TW Hya.

		Observation

Comp.	Parameter	TW Hya (1)^a	TW Hya (7435)	TW Hya (7436)	TW Hya (7437)	TW Hya (7435+7436)

	N_H^b (10²⁰ cm^-2)	10	10	10	10	10

Cool	T^b (MK)	2.5	2.5	2.5	2.5	2.5
	Ne^b (Ne_⊙)	1.2	1.2	1.2	1.2	1.2
	Fe^b (Fe_⊙)	0.2	0.2	0.2	0.2	0.2
	v_Xc (km s^-1)	44 ± 2	40 ± 4	47 ± 4	44 ± 4	44 ± 3
	Norm^c (10⁴)	76.7 ± 1.3	83.6 ± 2.1	102 ± 2.3	87.6 ± 2.2	81.3 ± 1.5

Hot	T (MK)	11.59 ± 0.15	11.13 ± 0.27	11.54 ± 0.24	12.02 ± 0.25	11.36 ± 0.18
	Ne (Ne_⊙)	1.38 ± 0.06	1.38 ± 0.12	1.38 ± 0.11	1.37 ± 0.10	1.39 ± 0.08
	Fe (Fe_⊙)	0.086 ± 0.004	0.084 ± 0.008	0.085 ± 0.007	0.087 ± 0.007	0.085 ± 0.005
	v_Xh (km s^-1)	25 ± 6	9.4 ± 10	25 ± 9	37 ± 9	19 ± 7
	Norm^c (10⁴)	1.51 ± .04	1.46 ± 0.07	1.88 ± 0.07	2.01 ± 0.08	1.46 ± 0.05

	7436 Norm^d	1.28 ± 0.02	...	...	...	1.28 ± 0.02
	7437 Norm^d	1.28 ± 0.02	...	...	...	...

Notes. All the errors refer to the 1σ level.

^(a)

This column reports the results obtained considering the combination of the ObsID 7435+7436+7437, we labeled it as TW Hya (1) in agreement with the rest of the work.

^(b)

Parameter fixed.

^(c)

Normalization parameter in units of where d is the distance to the source (cm), n_e is the plasma electron density (cm^-3), and n_H is the plasma hydrogen density (cm^-3).

^(d)

Global normalization constant applied multiplicatively to the whole model (both hot and cool components) in simultaneous fit.

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