We demonstrate a method for 2D velocity estimation in complex media characterized by triplicated ray fields. Due to multipathing, Migration Velocity Analysis (MVA) principle has to be revisited, requiring in particular the use of Common Angle Gathers (CAGs) instead of the classical common offset panels. For the inversion itself, locally coherent events are automatically picked in the prestack d...

We show with a short Chandra HRC-S exposure that the powerful X-ray source coincident with the nucleus of M33 is unresolved at the highest spatial resolution available to date (0. ′′ 4). The source flux is variable, doubling during the 5 ks exposure. The combination of properties exhibited by M33 X-8 establishes the source as the nearest example of the ultra-luminous X-ray sources that have bee...

We present the first interferometric 12 CO (J = 1 → 0) map of the entire Hα disk of M33. The 13 ′′ diameter synthesized beam corresponds to a linear resolution of 50 pc, sufficient to distinguish individual giant molecular clouds (GMCs). From these data we generated a catalog of 148 GMCs with an expectation that no more than 15 of the sources are spurious. The catalog is complete down to GMC ma...

The standard lower limit for the mass of white dwarfs (WDs) with a C/O core is roughly 0.5 M⊙. In the present work we investigated the possibility to form C/O WDs with mass as low as 0.33 M⊙. Both the pre-WD and the cooling evolution of such nonstandard models will be described.

We report optical photometric and spectroscopic observations of the M33 star B416, establishing it as the fifth identified LBV in that galaxy. The B magnitude of the star varies with a period of 8. 26 and an amplitude of 0.03 magnitude. The red end of the optical spectrum does not seem to partake in these oscillations, which we identify as the microvariations, known to persist in LBV stars. B41...

In prior work, Chandra and Gemini-North observations of the eclipsing X-ray binary M33 X-7 have yielded measurements of the mass of its black hole primary and the system’s orbital inclination angle of unprecedented accuracy. Likewise, the distance to the binary is known to a few percent. In an analysis based on these precise results, fifteen Chandra and XMM-Newton X-ray spectra, and our fully r...

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We construct a family of Order-Regular matrices of size m×n such that m ∼ Ω ( 10 √ 33 n) . Previously Order-Regular matrices were known only for m ∼ O (√ 2 n) .