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Abstract The microquasar SS 433 exhibits in H alpha intermittent flares, Doppler shifted to both the red and the blue. The mean remembers the orbital phase of the compact object. I show that the flares are not intermittent sightings of an accretion disk; rather, plasma must be expelled through the L2 point, thus remembering the phase of the orbit as it invades the space beyond the system. That space has been mapped with GRAVITY observations of a similar flare, revealing a strong rotation component., Comment: 9 pages, 4 Figures. arXiv admin note: text overlap with arXiv:0912.2428, arXiv:0708.2930

The Galactic microquasar SS 433 is a member of a binary system but there is a lack of data on the orbital velocities of the components. The emission lines of the C II doublet at 7231 and 7236 Angstrom have been tracked nightly over two orbital cycles. The spectra are adequate to establish that these lines are eclipsed by the companion and hence to extract a measure of the orbital velocity of the compact object; the lines are formed in the disk photosphere. This velocity is 176 plus/minus 13 km/s. Could XSHOOTER do better?, Comment: 7 pages, 3 figures

The jets of SS 433 have punched through the supernova remnant from the explosion forming the compact object. The precessing jets collimate before reaching beyond the shell, some 40 pc downstream, just the region of origin of TeV gamma radiation. Collimation could be effected by ambient pressure in the SNR cavity; I investigate conditions under which W50 morphology and the origins of TeV gamma radiation can be explained in terms of collimation, with associated shocks, induced by ambient pressure. I consider the age of the SNR and hence the present ambient pressure. The cavity is now ~ 10^5 years after the supernova; with lower pressure, collimation and associated shocks would occur ~40 pc downstream, just the origin of TeV gamma radiation. Modelling of evolution of binary systems indicates that Roche lobe overflow and initiation of the jets is recent. Collimation would still occur ~40 pc downstream, but the cone angle of the precession must then have increased with time - driven by the Roche lobe overflow. The morphology of W50 and the site of the origin of TeV gamma radiation are readily explained in terms of collimation of the jets by internal SNR pressure., Comment: Five pages, two figures. This version has been revised in the light of the HESS observations of TeV gamma radiation

Two recent and robust determinations of the mass ratio agree on a value 0.7, Comment: 6 pages, 2 figures

I discuss two points concerning recent Brackett series spectra of SS 433. The first is that outbursts to red and blue episodic in the Balmer series are now shown to be episodic in the far infrared Brackett series. The second point is that while in quiet times the Brackett profiles are characteristic of a disk rotating at ~ 200 km/s, such a disk is not the accretion disk and it should not be claimed that these profiles require a compact object mass less than 2.2 solar masses., Comment: 6 pages

The proper application of the virial theorem to the origin of osmotic pressure provides a simple, vivid and complete explanation of the physical processes involved; osmosis is driven by differential solvent pressures. This simple and intuitive notion is widely disregarded, but the virial theorem allows an exact formulation and unifies a number of different treatments. It is closely related to a kinetic treatment devised by Ehrenfest over 100 years ago., Comment: 11 pages, 2 figures. The revised version is expanded and polished. In particular it places the core material in context and makes explicit its relation to classic kinetic treatments of osmosis

Atomic oxygen emission at 8446 Angstroms traces the stable circumbinary disk undisturbed through an optical outburst and accompanying radio flare, Comment: The revised version of 2021 differs from the original in the addition of two figures and a section reporting that the source of 8446 Angstroms is NOT eclipsed

Some stationary lines in the emission spectra of SS 433 are eclipsed, but most are not. Lines attributed to a circumbinary disk are not eclipsed, but double in relative intensity during primary eclipse. A C II doublet is eclipsed and Doppler shifts over two periods yield an orbital speed of 176 +/- 13 km/s., Comment: 2 page note

The H and He emission lines of the microquasar SS 433 contain features that look very like emission from a circumbinary ring. Phenomenological models have been successful but contain certain ad hoc features. In this note the lines are treated as recombination lines from a highly ionized environment and differences between H and He, previously unexplained, are understood in terms of the different ionization potentials. It now seems inconceivable that these spectral features have origin other than in a circumbinary ring orbiting at approximately 250 km/s - in which case the system mass is approximately 40 solar masses., Comment: 6 pages, 7 figures. Submitted to A & A version 1.2 (25 Aug 13) has an additional section on the radiated intensity in H alpha. This is essentially the published version (see below)

If species abundance distributions are dominated by the simple processes of individuals in a community giving birth and death independently, the result is a log series distribution. I calculate this in a number of different ways, using both master equations and also the combinatoric methods of elementary statistical mechanics. Considerable light is shed on the nature and role of 'priors' in the language of MaxEnt., Comment: 9 pages. See also 2010 arXiv:1002.508

The Balmer H alpha emission line in the stationary spectrum of SS 433 has a component originating in the wind above the accretion disk. The Doppler motion of this line is a blurred representation of the motion of the compact object accreting. I show how this may be understood in terms of emission lasting over a few days, like radiation from the jet bolides., Comment: 4 pages, 3 figures. A coda to my circumbinary disk studies. To appear in A&A

In this brief note I draw attention to the structure of the stationary Halpha line as a function of orbital phase, using a data set compiled over some years. These data are compared with a set of nightly observations over some 2 orbits. The structures are very similar and this is highly relevant to the question of persistence and stability of spectral features which have been attributed to a circumbinary disk., Comment: 4 pages, 4 figures. Obvious qualitative similarities are quantified

Certain lines in spectra of the Galactic microquasar SS 433, in particular the brilliant H alpha line, have been interpreted as emission from a circumbinary disk. In this interpretation the orbital speed of the glowing material is in excess of 200 km/s and the mass of the binary system in excess of 40 solar masses. A very simple model of excitation of disk material is in remarkable agreement with the observations, yet it seems that the very existence of a circumbinary disk is regarded as controversial. Published spectra, taken almost nightly over two orbital periods of the binary system, show H alpha and He I lines; these were analysed as superpositions of Gaussian components. A model in which the excitation of any given patch of putative circumbinary material is proportional to the inverse square of its instantaneous distance from the compact object was constructed and compared with observations. The new model provides an excellent description of the observations. The variation of the H alpha and He I spectra with orbital phase are described quantitatively provided the radius of the emitting ring is not much greater than the radius of the closest stable circumbinary orbit. The new analysis has greatly strengthened the case for a circumbinary disk orbiting the SS 433 system with a speed of over 200 km/s and presents supposed alternative explanations with major difficulties. If the circumbinary disk scenario is essentially correct, the mass of the binary system must exceed 40 solar masses and the compact object must be a rather massive black hole. The case is so strong that this possibility should be taken seriously., Comment: 7 pages, 7 figures. The second version has two additional figures and an extended discussion. To appear in A & A

The Galactic microquasar SS\,433 is very luminous and launches oppositely-directed jets of cool hydrogen at a quarter of the speed of light. Observations of emission lines from the circumbinary disk imply a system mass exceeding 40 $ M_\odot$. The most recent attempts to establish a mass via observation of absorption lines in the spectrum of the companion imply a system mass of no more than 20 $ M_\odot$. Aims. To examine these conflicting data and present a possible resolution of this conflict. Methods. Interpretation of data through the application of simple trigonometry to the configuration of the SS 433 system. Results. The absorption spectra which, attributed to the atmosphere of the companion, yield an orbital speed of $\sim$ 60 km s$^{-1}$ could well be attributable to absorption of light from the companion in material of the circumbinary disk. Then the absorption spectra predict an orbital speed for the circumbinary disk material of $\sim$ 240 km s$^{-1}$, in agreement with the emission line data. Conclusions. If continuum light from the companion is absorbed in passage through the circumbinary disk material rather than in the atmosphere of the companion itself, the periodic Doppler shifts in the absorption spectra are entirely consistent with observations of the circumbinary disk and a system mass exceeding $\sim$ 40 $M_\odot$. The striking consistency implies that the compact object is a rather massive stellar black hole., Comment: This is a sequel to my article on the circumbinary disk of SS 433. arXiv:1004.0119v1 [astro-ph.GA]. The second version is 4 pages and has been augmented by 2 figures. The discussion has been somewhat extended to highlight the conditions necessary for this suggestion to apply

Context. The Galactic microquasar SS 433 is possessed of a circumbinary disk most clearly seen in the brilliant Balmer H alpha emission line. The orbital speed of the glowing material is an important determinant of the mass of the binary system. The circumbinary disk may be fed through the L2 point and in turn may feed a very extended radio feature known as the ruff. Aims. To present an analysis of spectroscopic optical data from H alpha and He I spectral lines which reveal the circumbinary disk. To use comparisons of the rather different signals to better understand the disk and improve estimates of the rotational speed of the inner rim. To present a simple model which naturally explains some apparently bizarre spectral variations with orbital phase. Methods. Published spectra, taken almost nightly over two orbital periods of the binary system, are analysed. H alpha and He I lines are analysed as superpositions of Gaussian components and a simple model constructed. Results. The data are understood in terms of a hot spot, generated by proximity of the compact object, rotating round the inner circumbinary disk with a period of 13 days. The glowing material fades with time, quite slowly for the H alpha source but more rapidly for the He I spectral lines. The orbital speed of the inner rim is approximately 250 km/s. Conclusions. The mass of the binary system must exceed 40 solar masses and the compact object must be a rather massive stellar black hole. The corollary is that the orbital speed of the companion must exceed 130 km/s., Comment: Article; 6 pages, 8 figures. The new version of 28 July 2010, to appear in A&A, is 8 pages and 8 figures. The principal addition is some discussion of the behaviour of a gas stream from the L2 point. I also have added a note about the possibility that absorption lines taken as indicating an orbital speed of 60 km/s for the companion might have their origin in the circumbinary disk

{The Galactic microquasar SS 433 is very luminous and ejects opposite jets at approximately one quarter the speed of light. It is regarded as a super-Eddington accretor but until recently there were no observations of accretion.} % aims heading (mandatory) {To present an analysis of spectroscopic optical data obtained before and during a major flare, which yield in H$\alpha$ unambiguous evidence for the accretion disk.} % methods heading (mandatory) {Published high resolution spectra, taken with a 3.6-m telescope almost nightly over 0.4 of a precession cycle, are analysed.} % results heading (mandatory) {Optical spectra taken almost nightly in August and September 2004 revealed a period of quiescence followed by activity which culminated in the accretion disk of SS433 becoming visible. The visible material in the accretion disk orbited the compact object at greater than 500 km s$^{-1}$, implying that the mass of the compact object is less than 37 $M_\odot$. Evidence that an accretion stream joins the disk at over 700 km s$^{-1}$ suggests that the mass is considerably below this upper limit. The accretion disk clearly orbits the centre of mass of the binary system with the compact object, sharing its speed of approximately 175 km s$^{-1}$. The mass of the companion lies between 20 and 30 $M_\odot$ and it probably does not fill its Roche lobe.}, Comment: 6 pages, 3 figures. This version to appear in A&A is a little more detailed than the original

Context. The Galactic microquasar SS 433 launches oppositely directed jets at speeds approximately a quarter of the speed of light. Both the speed and direction of the jets exhibit small fluctuations. A component of the speed variation has 13 day periodicity and the orbital phase at which its maximum speed occurs has advanced approximately 90 degrees in 25 years. Aims. To examine the possibility that these variations are associated with a mildly eccentric orbit and conditions necessary to achieve this apsidal advance. Methods. The advance of the orbital phase for maximum speed is taken to be advance of the apses of the putative elliptical orbit. It is compared with calculations of the effects of tides induced in the companion and also with gravitational perturbations from the circumbinary disc. These calculations are made in the light of recent results on the SS 433 system. Results. The 13 day periodicity in the speed of the jets of SS 433 might be attributed to a mildly elliptical orbit, through periodic approaches of the donor and the compact object. Advance of the apses of such an elliptical orbit due to tidal effects induced in a normal companion looks to be to small; if caused by the circumbinary disc the mass of the inner regions of that disc is ~ 0.15 solar masses., Comment: 2 pages, no figures To appear in A & A. No significant changes from original version posted