VLT/UVES spectroscopy of the O supergiant companion   to 4U 1907+09(7)

Cox, N. L. J.; Kaper, L.; Mokiem, M.R.

doi:10.1051/0004-6361:20040511

Cited by 42 publications

(61 citation statements)

References 37 publications

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“…Optical and infrared observations (Cox et al 2005;Nespoli et al 2008) suggest an O8-O9 Ia type supergiant donor with L ∼ 5 × 10 5 L and a mass-loss rate of about 7 × 10 −6 M yr −1 . The supergiant nature of the companion and the strong X-ray variability indicate that accretion most likely proceeds from a stellar wind.…”

Section: Introductionmentioning

confidence: 98%

Supergiant, fast, but not so transient 4U 1907+09

Doroshenko

Santangelo

Ducci

et al. 2012

A&A

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We have investigated the dipping activity observed in the high-mass X-ray binary 4U 1907+09 and shown that the source continues to pulsate in the "off" state, noting that the transition between the "on" and "off" states may be either dip-like or flare-like. This behavior may be explained in the framework of the "gated accretion" scenario proposed to explain the flares in supergiant fast X-ray transients (SFXTs). We conclude that 4U 1907+09 might prove to be a missing link between the SFXTs and ordinary accreting pulsars.

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Section: Introductionmentioning

confidence: 98%

Supergiant, fast, but not so transient 4U 1907+09

Doroshenko

Santangelo

Ducci

et al. 2012

A&A

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“…Hence, NIR spectroscopic (DIB) surveys may reveal their presence in the interstellar medium (ISM). Several ongoing and A&A 569, A117 (2014) Cox et al (2005) and HD 161061 taken from Mazzei & Barbaro (2011) . (b) Intrinsic colours from (1) Wegner (1994) and (2) Fitzgerald (1970).…”

Section: Introductionmentioning

confidence: 99%

VLT/X-Shooter survey of near-infrared diffuse interstellar bands

Cox

Cami

Kaper

et al. 2014

A&A

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Context. The unknown identity of the diffuse interstellar band (DIB) carriers poses one of the longest standing unresolved problems in astrophysics. While the presence, properties, and behaviour of hundreds of optical DIBs between 4000 Å and 9000 Å have been well established, information on DIBs in both the ultra-violet and near-infrared (NIR) ranges is limited. Aims. In this paper, we present a spectral survey of the NIR range, from 0.9 µm to 2.5 µm. Our observations were designed to detect new DIBs, confirm previously proposed NIR DIBs, and characterise their behaviour with respect to known line-of-sight properties (including the optical DIBs present in our spectra). Methods. Using the X-Shooter instrument mounted on the ESO Very Large Telescope (VLT) we obtained medium-resolution spectra of eight known DIB targets and one telluric reference star, from 3000 Å to 25 000 Å in one shot.Results. In addition to the known 9577, 9632, 10 780, 11 797, and 13 175 Å NIR DIBs, we confirm 9 out of the 13 NIR DIBs that were presented by Geballe et al. (2011, Nature, 479, 200). Furthermore, we report 11 new NIR DIB candidates. The strengths of the strongest NIR DIBs show a general correlation with reddening, E (B − V) , but with a large scatter. Several NIR DIBs are more strongly correlated with the 5780 Å DIB strength than with E (B − V) ; this is especially the case for the 15 268 Å DIB. The NIR DIBs are strong: the summed equivalent widths of the five strongest NIR DIBs represent a small percent of the total equivalent width of the entire average DIB spectrum (per unit reddening). The NIR DIBs towards the translucent cloud HD 147889 are all weak with respect to the general trend. No direct match was found between observed NIR DIBs and laboratory matrix-isolation spectroscopic data of polycyclic aromatic hydrocarbons (PAHs). Conclusions. The strong correlation between the 5780−15 268 DIB pair implies that (N f ) 5780 /(N f ) 15 268 = 14. However, the reduced strength of the 15 268 Å DIB in HD 147889 rules out a common carrier for these two DIBs. Since the ionisation fraction for small PAHs in this translucent cloud is known to be low compared to diffuse clouds, the weakness of the 15 268 Å DIB suggests that an ionised species could be the carrier of this NIR DIB.

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“…A distance d = 2.1−2.6 kpc was derived by van Kerkwijk et al (1989) and Cox et al (2005) from interstellar absorption of sodium in the spectrum of 4U 1907+09, while the detection of a high-velocity (∼60 km s −1 ) component in the K i absorption line in the line-of-sight towards 4U 1907+09 suggests a distance of ≥4 kpc (Cox et al 2005). The latter estimate is based on the model of Galactic rotation by Brand & Blitz (1993), which assumes that, to first order, the Galactic velocity field is axisymmetric.…”

Section: U 1907+09: General Datamentioning

confidence: 97%

“…This belief was boosted after Chatterjee et al (2005) derived a space velocity of ∼1000 km s −1 for the pulsar PSR Nespoli et al (2008). (b) Cox et al (2005). (c) Conti (1978).…”

Section: Asymmetric Supernova Explosionmentioning

confidence: 99%

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4U 1907+09: an HMXB running away from the Galactic plane

Gvaramadze

Röser

Scholz

et al. 2011

A&A

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We report the discovery of a bow shock around the high-mass X-ray binary (HMXB) 4U 1907+09 using the Spitzer Space Telescope 24 μm data (after Vela X-1 the second example of bow shocks associated with HMXBs). The detection of the bow shock implies that 4U 1907+09 is moving through space with a high (supersonic) peculiar velocity. To confirm the runaway nature of 4U 1907+09, we measured its proper motion, which for an adopted distance to the system of 4 kpc corresponds to a peculiar transverse velocity of 160 ± 115 km s −1 , meaning that 4U 1907+09 is indeed a runaway system. This also supports the general belief that most HMXBs possess high space velocities. The direction of motion of 4U 1907+09 inferred from the proper motion measurement is consistent with the orientation of the symmetry axis of the bow shock, and shows that the HMXB is running away from the Galactic plane. We also present the Spitzer images of the bow shock around Vela X-1 (a system similar to 4U 1907+09) and compare it with the bow shock generated by 4U 1907+09.

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VLT/UVES spectroscopy of the O supergiant companion to 4U 1907+09(7)

Cited by 42 publications

References 37 publications

Supergiant, fast, but not so transient 4U 1907+09

Supergiant, fast, but not so transient 4U 1907+09

VLT/X-Shooter survey of near-infrared diffuse interstellar bands

4U 1907+09: an HMXB running away from the Galactic plane

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