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Questions tagged [x-ray]

Questions regarding the second-shortest wavelength of light.

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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 ...
Walker's user avatar
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4 votes
1 answer
439 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.
Walker's user avatar
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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 ...
uhoh's user avatar
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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 ...
riemannium's user avatar
1 vote
0 answers
48 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 ...
Jimmy Bionic's user avatar
2 votes
2 answers
105 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). ...
martín canullán's user avatar
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 ...
martín canullán's user avatar
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 ...
Deko Revinio's user avatar
6 votes
1 answer
341 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 ...
Mark Foskey's user avatar
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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 ...
RonJohn's user avatar
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6 votes
1 answer
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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 ...
uhoh's user avatar
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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 ...
uhoh's user avatar
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2 votes
1 answer
115 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 ...
uhoh's user avatar
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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 ...
WGroleau's user avatar
  • 141
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 (...
uhoh's user avatar
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2 votes
1 answer
67 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 ...
usernumber's user avatar
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-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 ...
Alex's user avatar
  • 701
3 votes
1 answer
66 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 ...
quantumflash's user avatar
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 ...
uhoh's user avatar
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0 votes
1 answer
578 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 ...
theWrongAlice's user avatar
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?
Monkey King's user avatar
1 vote
2 answers
128 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.
theWrongAlice's user avatar
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 ...
Monkey King's user avatar
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 ...
theWrongAlice's user avatar
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, ...
Richard's user avatar
  • 323
2 votes
1 answer
117 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 ...
Chen's user avatar
  • 339
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 ...
uhoh's user avatar
  • 30.8k
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 ...
Serge Stroobandt's user avatar
3 votes
1 answer
137 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 ...
uhoh's user avatar
  • 30.8k
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 ...
Hrsht's user avatar
  • 333
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 ...
Allure's user avatar
  • 4,554
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 ...
uhoh's user avatar
  • 30.8k
5 votes
1 answer
266 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 ...
Robyn's user avatar
  • 191
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'...
Ronald Swager's user avatar
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 ...
HDE 226868's user avatar
  • 36.6k
1 vote
1 answer
536 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 ...
jasmine1323's user avatar
-4 votes
1 answer
271 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 ...
S C Sawhney's user avatar
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 ...
Harsh Kumar's user avatar
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-...
HDE 226868's user avatar
  • 36.6k
8 votes
1 answer
986 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 ...
uhoh's user avatar
  • 30.8k
1 vote
1 answer
94 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 ...
zeitoon's user avatar
  • 190
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 ...
questionhang's user avatar
  • 3,137
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 ...
Mark Foskey's user avatar
  • 3,916
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 ...
TheLabyrinthMaker's user avatar
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 ...
questionhang's user avatar
  • 3,137
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 ...
LocalFluff's user avatar
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