#papertime — Public Fediverse posts

#Papertime

Vander Meulen, Hu, Grinberg & Krawczynski (A&A submitted): "Predictions for the X-ray polarisation modulation in Cygnus X-1 from reflection off the stellar companion and its wind"

-- we set up a radiative transfer model combining a general relativistic description of the polarised source emission + focussed stellar wind model to show effects of the stellar wind & reflection off companion star on X-ray polarization:

▶️ https://arxiv.org/abs/2606.04159

#ArXiv #astrodon #XraysAreTheBestRays

#Papertime! "Characterisation of the stellar wind in Cyg X-1 via modelling of colour-colour diagrams" by E. V. Lai et al., including yours truly

▶️ https://arxiv.org/abs/2408.05852

I especially love this paper because a PhD student read a paper of mine, took the method I developed there (https://ui.adsabs.harvard.edu/abs/2020A%26A...643A.109G/abstract), cleverly applied it to her data and developed a statistical approach to evaluate the models vs. the data, a step my original proposal did not make.

#astrodon #XraysAreTheBestRays

#PaperTime! (From Monday, but I was too sick to post then.)

Bouchet et al., A&A accepted:
"INTEGRAL/IBIS polarization detection in the hard and soft intermediate states of Swift J1727.8-1613"
https://arxiv.org/abs/2407.05871

(Soft) gamma-ray #polarization has been detected in black hole X-ray binaries in the hard state (i.e. when strong jets are present) and interpreted as due to synchrotron from the jets. For the first time, we detect such polarization in other states!

#astrodon #XraysAreTheBestRays

#PaperTime from yesterday's #ArXiv

Steiner et al., incl. me + @astrobianchi
"An #IXPE-Led X-ray Spectro-Polarimetric Campaign on the Soft State of Cygnus X-1: X-ray Polarimetric Evidence for Strong Gravitational Lensing"

➡️ https://ui.adsabs.harvard.edu/abs/2024arXiv240612014S/abstract , ApJ accepted

🤯 Soft X-ray polarization in the black hole X-ray binary Cygnus X-1 can be explained by returning radiation, i.e. radiation from the disk returning back due to GR effects & reflected off the disk!

1/3

#astrodon #XraysAreTheBestRays

#Papertime! 🌌 💫 📡 (From Monday, but I totally did not have the time to post this before ...)

"The first mm detection of a neutron star high-mass X-ray binary" led by the amazing J. van den Eijnden, including @fuerst, @pkretsch, yours truly et al.
MNRAS submitted (not yet refereed).

▶️ https://ui.adsabs.harvard.edu/abs/2023arXiv230806021V/abstract

What is this about and why is this important? Follow along for a science 🧵

#Astrodon #astronomy #XraysAreTheBestRays #astrophysics
1/7

#papertime 🥳

Where we use a method originally used for AGN to answer the question whether
we can use variability in individual X-ray lines to probe the variable stellar wind.

And the answer is: yes, we can!

The paper (submitted not yet refereed) is:

"Stellar wind variability in Cygnus X-1 from high-resolution excess
variance spectroscopy with Chandra" by Härer et al.
https://arxiv.org/abs/2304.14201

Let me disentangle what the title means: 1/6

#astrodon #BlackHole #VicisAstro #astronomy #SciArt