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Questions tagged [x-ray]

Questions regarding the second-shortest wavelength of light.

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4 votes
1 answer
440 views

Light curves for Chandra

I am working with Chandra data. I only have the corrected PI files for the sources. Is there a way to plot the light curve from this PI file. I wanted to extract the color magnitude ultimately.
1 vote
0 answers
41 views

plotting light curve for x ray data

how can I plot the light curve for Chandra X-ray data? I want to extract the counts within the specified energy range from the light curve. e.g., I have to extract the counts within the energy range ...
0 votes
0 answers
60 views

Looking straight through the Milky Way Galaxy with the Gedanken Space Telescope from radio to 100 keV, what would the opacity vs wavelength look like?

Imagine that the "Large Gedanken Cryogenic Space Telescope" has been commissioned and aligned and is ready for its first test. It is equipped with a closed-cycle helium refrigerator to ...
1 vote
0 answers
21 views

How to determine semiamplitude from Julian Date data?

How could I determine semiamplitude from these data for NGC300 X-1 without fitting, only with data of phase and JD? This is a common problem for exoplanets, X-ray binaries and other general binary ...
11 votes
1 answer
268 views

Why would a black hole have a disk, but not emit x-rays?

There's a recent paper in Nature about LB-1, a B-class star orbiting a massive black hole. I don't understand how these two parts of the paper can be reconciled. On page 2, the authors argue that the ...
15 votes
3 answers
4k views

What happens when the quasar remnants reach Earth in 3 million years?

According to this article (A quasar Milky Way six million years ago?), during: (during) a quasar stage in its evolution (6 million years ago) ... the Milky Way’s central black hole swallowed a huge ...
1 vote
0 answers
49 views

Number of neutron stars by radiation band

Since the number of known neutron stars ain't reached yet 4000 at the time of writing, I am wondering about how neutron stars are classified in terms of their radiation spectrum. Clearly, some neutron ...
-2 votes
2 answers
158 views

Could observation of GL or other image phenomena from system of 2 merging massive dense objects and of GW caused by their merge be connected?

What is the probability to observe gravitational lensing (or any other image related phenomena) from the pair of black holes (or pair of neutron stars or black hole - neutron star) which are about to ...
2 votes
2 answers
107 views

Supernova remnant spectral lines

I have some trouble to find which spectral lines are the ones in this SNR N49 fitted spectrum. They are at 1.3 keV, 1.9keV, 2.5keV, 3.2keV, 3.95keV and maybe at 0.65keV and 6.8keV (approximately). ...
3 votes
0 answers
34 views

Supernova remnant and ejecta "bullet"

I'm making an X-ray analysis of the source SNR N49. It has a magnetar inside of it that is emitting strongly in Soft ([0.2-1.2] keV), Medium ([1.2-2.5] keV), and Hard ([2.5-8.0] keV) bands. I was ...
3 votes
1 answer
1k views

Are these images of the same nebula?

This image from the Spitzer telescope is supposedly of the Orion nebula. But this image from the Chandra telescope also claims to be of the Orion nebula. I have been unable to confirm either of these ...
6 votes
1 answer
343 views

Are X-ray rings around GRBs analogous to sun halos?

This APOD image shows two nested rings in the X-ray spectrum surrounding a gamma ray burst. Or maybe I should consider it to be a single ring around a disc. The APOD description says, ...the X-rays ...
2 votes
0 answers
63 views

What methodology should be used to choose the correct model for origin of QPOs in X-ray astronomy?

In X-ray astronomy, quasi periodic oscillations (QPOs) are routinely shown by black hole and neutron star X-ray binary systems in their X-ray flux. Despite being strong and easily measurable signals, ...
6 votes
1 answer
116 views

How do neutron stars maintain inhomogeneous surfaces and migrating "hot spots"? (e.g. SGR 1830-0645)

News item NASA's NICER Tracks a Magnetar's Hot Spots and Phys.org's Properties of magnetar SGR 1830−0645 inspected with NICER reference the January 14 2022 arXiv Pulse Peak Migration during the ...
5 votes
1 answer
268 views

What are the curved lines in this X-ray image of the sky?

This image was created using the NICER instrument on the ISS. Source: https://www.nasa.gov/feature/goddard/2019/nicer-s-night-moves-trace-the-x-ray-sky What are the big curves between the X-ray ...
6 votes
1 answer
147 views

What are the main ways that pulsar "glitches" are noticed and documented? Do they have to be caught in the act of glitching to be catalogued?

This answer to Is there any well-populated list or database of pulsar "glitches"? mentions two large databases; (Jodrell Bank and ATNF's pulsar catalog) but neither question nor answer ...
6 votes
2 answers
128 views

After only one eclipse of its X-ray bright primary, how can astronomers estimate the first extragalactic exoplanet's period to be about 70 years?

Phys.org's Astronomers may have discovered the first planet outside of our galaxy links to Di Stefano et al. 2021 A possible planet candidate in an external galaxy detected through X-ray transit (...
2 votes
1 answer
116 views

How does IXPE measure polarization, and why does it have three identical X-ray telescopes?

From The Observatory: Anyone who missed any of the AAS 239 press conferences can see them on the AAS Press Office's YouTube channel! Here's the full program. From there I found the Monday, January ...
1 vote
0 answers
87 views

Satellite emitting x-rays? [closed]

On the local TV news, it was alleged that x-rays from some satellite could interfere with something on earth. I didn't hear it but my wife thought they were talking about WiFi or internet or ...
2 votes
1 answer
94 views

What is in this soft x-ray image?

I've been exploring this new ESA tool and I came across this structure. What is it? The circles look like they might be the footprint of a telescope. Perhaps there was a survey of this specific ...
4 votes
1 answer
148 views

How is it determined that the X-ray and radio intensity come from a magnetic field bridge between two clusters of galaxies?

Gizmodo's Astronomers Spot Mysterious, 10-Million-Light-Year-Long Magnetic Field Connecting Two Galaxy Clusters shows the image below, and Space.com's A Weird 'Radio Bridge' 10 Million-Light Years ...
2 votes
1 answer
118 views

What does "the depth of the 13.0 Å feature differs by 7 sigma from zero" mean?

In a paper I've read, I have seen the following: In view of the noise levels, it is difficult to perform such a search effectively using statistical significance criteria only. We will therefore ...
3 votes
1 answer
68 views

Is it possible to observe Lyman-continuum emission from extragalactic objects?

Lyman-continuum (LyC) emission is everything blueward of 912 Angstroms (so it includes extreme UV photons, X-rays and gamma rays). There are many low-redshift astrophysical plasmas such as the diffuse ...
3 votes
1 answer
149 views

Are X-ray telescopes with glancing angle surfaces basically "funny-looking" Cassegrain telescopes mathematically?

In this answer I included the image below of a reflective X-ray telescope. It is made from two elements; the first is concentric shells of glancing (high incidence) angle paraboloidal surfaces, and ...
0 votes
1 answer
589 views

How to calculate galaxy bolometric luminosity?

I am a bit confused by bolometric corrections. If I have an x-ray luminosity in the 2-10 keV band, how does one convert that to $L_{bol}$? From Netzer's book The Physics and Evolution of Active ...
5 votes
2 answers
7k views

What is "emission measure"?

Many papers mention emission measure, and some of them give the expression of EM, BUT there is no clear definition of EM. My question is what EM is on earth? Its unit is supposed to be cm-3. How to ...
15 votes
1 answer
1k views

How can the Sun block an X-ray telescope from observing a QPO galaxy "for several years"?

Phys.org's Black hole's heart still beating says: X-ray satellite observations spotted the repeated beat after its signal had been blocked by our Sun for a number of years. and links to the Open ...
2 votes
3 answers
2k views

What is a hard spectral state vs. a soft spectral state?

In X-ray astronomy, the source is considered to be in the hard or soft spectral state. So what is the meaning of the hard spectral state? What are the soft state and hard state in spectroscopy?
1 vote
2 answers
131 views

What is the lifetime of an x-ray binary?

What would be the typical lifetime of an x-ray binary? I have trouble finding a reference.
1 vote
0 answers
83 views

What is the relation between between hardness ratio(HR) and spectral state of a X-ray binary star system?

When reading about hardness ratio, it shows that depending on the hardness ratio spectral states of a binary star can be divided into soft, hard states. So how the HR value changes with respect to the ...
1 vote
1 answer
538 views

How to shift an AGN X-ray spectrum to rest frame

I have limited information to shift a spectrum (in the X-ray 0.5-10 keV bandpass) from redshift $z=2$ to the rest frame. I have a plot of normalized (photon) counts s$^{−1}$ keV$^{−1}$ as a function ...
4 votes
0 answers
70 views

K-correction vs resizing photometric bands

Is there a difference between a K-correction (see Wiki https://en.wikipedia.org/wiki/K_correction) and simply "resizing" the bands, e.g. the 2-10 keV x-ray band, with the redshift? I've read ...
1 vote
1 answer
46 views

Any active solar X-ray imager in orbit?

NOAA GOES-14 & 15 went very recently in storage mode. With those also went the solar X-ray imagers (SXI), as GOES-16 & 17 do not have such instruments on board. Hence, my question: Are there ...
3 votes
1 answer
139 views

How does the field decay of a magnetar power the emission of high-energy electromagnetic radiation?

In Space.com's Dr. Pulsar and Mr. Magnetar? 2 Star Types May Turn into Each Other (and in the linked video) "Tom Prince, a physics professor at the California Institute of Technology and a senior ...
9 votes
1 answer
2k views

What are optical counterparts?

There surprisingly no proper definition of this term available on google. There are many research papers that are based on "finding the optical counterparts". What exactly are optical counterparts ...
5 votes
1 answer
113 views

Is there evidence of super-heavy elements in the x-ray and gamma-ray spectrums of neutron stars?

It occurs to me, that between the surface and interior of neutron stars, gravitational pressure might produce super-heavy elements and that signatures of such elements might be detectable in the star'...
6 votes
1 answer
187 views

Do narrow lines in the spectra of O- and B- type stars always indicate magnetic fields?

I was reading a paper on the differential emission measures of a set of hot O- and B- type stars. As the authors discuss in Section 3 (page 959), two stars, $\tau$ Sco and $\theta^1$ Ori C, have ...
-4 votes
1 answer
273 views

If sun-rays also contain any X-rays why we can't see the inner organs of the human body through these rays? [closed]

Nobody has been able to find an answer how anybody may be able to see the inner organs of the human body as Natalya Demkina is able to see. In this context, I want to mention that the same way as we ...
4 votes
0 answers
62 views

How can X-rays be emitted from a black hole? [duplicate]

A black hole's gravity prevents light from escaping, how can a black hole emit X-rays? Visible light and X-rays are both electromagnetic radiation, shouldn't the black hole's gravity prevent X-rays ...
2 votes
1 answer
90 views

In Chromoscope, what is the X-ray source between Ophiuchus, Libra and Scorpius?

Chromoscope is a nice toy. Pressing 'L' shows the constellations as guide. There's a bright X-ray source between Ophiuchus, Libra and Scorpius. In Hydrogen-Alpha there are two circular formations to ...
2 votes
2 answers
99 views

Why is there a density dropoff in the stellar winds of magnetic O-type stars?

I recently went to a talk on X-ray emissions from stellar winds of O-type stars, and a paper was explored that in turn referenced ud-Doula et al. (2014). Essentially, O-type stars may show strong x-...
8 votes
1 answer
987 views

Plot of best available resolution vs wavelength - radio through gamma rays?

What I'm looking for is a graphic that shows in a general way the best available telescope resolution vs wavelength throughout the entire wavelength spectrum. So for example, there might be two very ...
1 vote
1 answer
95 views

What does less than one count from an x-ray detector mean? (Swift BAT detector)

I'm reading a paper about a recent x-ray burst from a suspected magnetar (A. Dai et al 2016) where they show a light curve of a burst that lasted about 10ms. (Their figure 1). The value of count rate ...
3 votes
1 answer
67 views

Stratospheric Balloon with an Xray camera

Some colleagues and I were planning to launch a stratospheric balloon in December. A thought occurred to me: what if we were to put some sort of xray camera in the payload? We are expecting a maximum ...
5 votes
1 answer
245 views

Are high-speed galactic collisions survivable?

This is a hypothetical question, but it really is meant as a vivid way of asking about the affects of high-speed galactic collisions. The November 27 APOD showed the Cheshire Cat galaxy group, and the ...
1 vote
1 answer
63 views

accretion discs in h/lmxbs

High mass x-ray binaries necessarily accrete via wind, no disc accretion? What makes the difference between a hmxb and a lmxb? In what kind of circumstances does an accretion disc form? How does it ...