scholarly journals Discovery of annular X-ray emission centered on MAXI J1421-613: Dust-scattering X-rays?

2020 ◽  
Vol 72 (2) ◽  
Author(s):  
Kumiko K Nobukawa ◽  
Masayoshi Nobukawa ◽  
Shigeo Yamauchi
Keyword(s):  
Time History ◽  
Rare Condition ◽  
X Rays ◽  
X Ray ◽  
Transient Source ◽  
Hydrogen Column Density ◽  
Photon Index ◽  
Absorbed Power ◽  
Short Time

Abstract We report the discovery of an annular emission of $\sim\!\! {3^{\prime }}\!-\!{9^{\prime }}$ radius around the center of a transient source, the X-ray burster MAXI J1421-613, in the Suzaku follow-up analysis. The spectrum of the annular emission shows no significant emission-line structure, and is well explained by an absorbed power-law model with a photon index of $\sim\!\! 4.2$. These features exclude the possibility that the annular emission is a shell-like component of a supernova remnant. The spectral shape, the time history, and the X-ray flux of the annular emission agree with the scenario that the emission is due to a dust-scattering echo. The annular emission is made under a rare condition of the dust-scattering echo, where the central X-ray source, MAXI J1421-613, exhibits a short time outburst with three X-ray bursts and immediately re-enters a long quiescent period. The distribution of the hydrogen column density along the annular emission follows that of the CO intensity, which means that MAXI J1421-613 is located behind the CO cloud. We estimate the distance to MAXI J1421-613 to be $\sim\!\! 3\:$kpc assuming that the dust layer responsible for the annular emission is located at the same position as the CO cloud.

scholarly journals Detection of X-ray flares from AX J1714.1−3912, the unidentified source near RX J1713.7−3946

2018 ◽  
Vol 612 ◽  
pp. A32 ◽  
Author(s):  
Marco Miceli ◽  
Aya Bamba
Keyword(s):  
Supernova Remnants ◽  
Time Variability ◽  
X Rays ◽  
Energy Bands ◽  
X Ray ◽  
Nonthermal Emission ◽  
Photon Index ◽  
Unidentified Source

Context. Molecular clouds are predicted to emit nonthermal X-rays when they are close to particle-accelerating supernova remnants (SNRs), and the hard X-ray source AX J1714.1−3912, near the SNR RX J1713.7−3946, has long been considered a candidate for diffuse nonthermal emission associated with cosmic rays diffusing from the remnant to a closeby molecular cloud. Aim. We aim at ascertaining the nature of this source by analyzing two dedicated X-ray observations performed with Suzaku and Chandra. Methods. We extracted images from the data in various energy bands, spectra, and light curves and studied the long-term evolution of the X-ray emission on the basis of the ~4.5 yr time separation between the two observations. Results. We found that there is no diffuse emission associated with AX J1714.1−3912, which is instead the point-like source CXOU J171343.9−391205. We discovered rapid time variability (timescale ~ 103 s), together with a high intrinsic absorption and a hard nonthermal spectrum (power law with photon index Γ ~ 1.4). We also found that the X-ray flux of the source drops down by 1–2 orders of magnitude on a timescale of a few years. Conclusions. Our results suggest a possible association between AX J1714.1−3912 and a previously unknown supergiant fast X-ray transient, although further follow-up observations are necessary to prove this association definitively.

scholarly journals Probing the nature of AX J0043−737: Not an 87 ms pulsar in the Small Magellanic Cloud

2018 ◽  
Vol 612 ◽  
pp. A87 ◽  
Author(s):  
C. Maitra ◽  
J. Ballet ◽  
P. Esposito ◽  
F. Haberl ◽  
A. Tiengo ◽  
...  
Keyword(s):  
Active Galactic Nucleus ◽  
Magellanic Cloud ◽  
Field Of View ◽  
Common Phenomenon ◽  
Small Magellanic Cloud ◽  
X Ray ◽  
Photon Index ◽  
Absorbed Power

Aims. AX J0043−737 is a source in the ASCA catalogue whose nature is uncertain. It is most commonly classified as a Crab-like pulsar in the Small Magellanic Cloud (SMC) following apparent detection of pulsations at ~87 ms from a single ASCA observation. A follow-up ASCA observation was not able to confirm this, and the X-ray detection of the source has not been reported since. Methods. We studied the nature of the source with a dedicated XMM-Newton observation. We ascertained the source position, searched for the most probable counterpart, and studied the X-ray spectrum. We also analysed other archival observations with the source in the field of view to study its long-term variability. Results. With the good position localisation capability of XMM-Newton, we identify the counterpart of the source as MQS J004241.66–734041.3, an active galactic nucleus (AGN) behind the SMC at a redshift of 0.95. The X-ray spectrum can be fitted with an absorbed power law with a photon-index of Γ = 1.7, which is consistent with that expected from AGNs. By comparing the current XMM-Newton observation with an archival XMM-Newton and two other ASCA observations of the source, we find signatures of long-term variability, another common phenomenon in AGNs. All of the above are consistent with AX J0043−737 being an AGN behind the SMC.

Classification of Fresh Fractures of the Lunate

1988 ◽  
Vol 13 (4) ◽  
pp. 458-462
Author(s):  
H. TEISEN ◽  
J. HJARBAEK
Keyword(s):  
Vascular Anatomy ◽  
X Rays ◽  
Lunate Bone ◽  
X Ray

The X-rays of 17 patients with fresh fractures of the lunate bone have been reviewed. The fractures were classified according to their radiological appearances and according to the vascular anatomy of the lunate. A long term X-ray follow-up examination was performed.

159 The Need Of Six Monthly Follow Up X-Rays Post Total Knee Replacement(TKR)

2021 ◽  
Vol 108 (Supplement_6) ◽  
Author(s):  
N Baig ◽  
M Ferrari ◽  
A Lukaszewicz
Keyword(s):  
Total Knee Replacement ◽  
Knee Replacement ◽  
Trauma Centre ◽  
X Rays ◽  
Data Set ◽  
X Ray ◽  
Major Trauma Centre ◽  
Plain Films ◽  
Total Knee

Abstract Background There is a longstanding culture of repeat x-rays after total knee replacement (TKR) as part of follow up, often combined with a clinic review. This is to check that the prosthesis is in a satisfactory position. There are inherently a number of issues with this historic approach including exposure of patients to further radiation who may be asymptomatic, time delays in busy clinics or x-ray departments and costs. Objectives The aim of this audit was to assess whether follow up plain films after TKR are methodically undertaken and of benefit to confirm satisfactory appearance if immediate post -operative x-rays were unremarkable. The findings of a six month follow up x-ray was specifically evaluated. The secondary aim was to establish the timing of further follow up x-rays within the department. Method 200 patients were included within the analysis, they all received a TKR at a major trauma centre, over a one-year period between December 2017 and December 2018. Results It was found that 100% of those patients having a post-operative film had a satisfactory appearance. 78% of patients had at least one further follow op x-ray of which 99.4% were satisfactory. Up to five follow up x-rays were taken with 53.5% of patients having a follow up x-ray at 6 months. Conclusions From the above results there is minimal, if any, evidence within the data set to support routine, additional follow up imaging if initial post-operative films are satisfactory, and the patient is asymptomatic.

scholarly journals Optical Short-Time Variations in GK Persei during the 1983 Outburst

1987 ◽  
Vol 93 ◽  
pp. 485-485
Author(s):  
H. Steinle ◽  
W. Pietsck
Keyword(s):  
Accretion Disk ◽  
Time Resolution ◽  
X Rays ◽  
X Ray ◽  
Time Variations ◽  
Short Time ◽  
First Time ◽  
Calar Alto

AbstractDuring the August 1983 outburst of the old nova GK Persei observations with EXOSAT showed for the first time a 351 second periodicity in X-rays.Our fast photometry (U(B)V with 25 sec time resolution) was made at the end of the outburst in the nights of September 29 , and October 1–3 , using the 2.2 meter telescope at Calar Alto (Spain).Optical variations up to 10% in U and 4% in V with periodicities in the range 350 to 360 seconds were found, lasting only for few cycles.A comparison with the extrapolated prediction of the X-ray maxima did not show a coincidence, but rather an anticoincidence in several cases. This supports a model of reprocessed X-rays at the inner edge of an accretion disk.

Isoelastic Cementless Total Hip Replacement in Rheumatoid Arthritis. Long-Term Results

1992 ◽  
Vol 2 (2) ◽  
pp. 43-46
Author(s):  
U. Fusco ◽  
R. Capelli ◽  
A. Avai ◽  
M. Gerundini ◽  
L. Colombini ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Hip Replacement ◽  
The Other ◽  
Long Term Results ◽  
X Rays ◽  
X Ray ◽  
The Mean ◽  
Cementless Total Hip Replacement

Between 1980 and 1987 we have implanted 46 isoelastic cementless THR in 40 patients affected with rheumatoid arthritis. We have reviewed 38 hips clinically and by X-ray. The mean follow-up was 8,5 years. Harris hip scores ranged from 30.6 preoperatively to 73,4 post-operatively when reviewed. While on the other hand Merle D'Aubigné hip scores ranged from 7,06 pre-operatively to 15,59 post-operatively. All patients have been satisfied, and X-rays showed an improvement for both Charnely and Gruen X-ray score.

scholarly journals Prolonged sub-luminous state of the new transitional pulsar candidate CXOU J110926.4−650224

2019 ◽  
Vol 622 ◽  
pp. A211 ◽  
Author(s):  
Francesco Coti Zelati ◽  
Alessandro Papitto ◽  
Domitilla de Martino ◽  
David A. H. Buckley ◽  
Alida Odendaal ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Broad Band ◽  
Optical Emission ◽  
Bimodal Distribution ◽  
X Ray ◽  
The Past ◽  
Upper Limits ◽  
Photon Index ◽  
Multi Wavelength ◽  
Absorbed Power

We report on a multi-wavelength study of the unclassified X-ray source CXOU J110926.4−650224 (J1109). We identified the optical counterpart as a blue star with a magnitude of ∼20.1 (3300–10500 Å). The optical emission was variable on timescales from hundreds to thousands of seconds. The spectrum showed prominent emission lines with variable profiles at different epochs. Simultaneous XMM-Newton and NuSTAR observations revealed a bimodal distribution of the X-ray count rates on timescales as short as tens of seconds, as well as sporadic flaring activity. The average broad-band (0.3–79 keV) spectrum was adequately described by an absorbed power law model with photon index of Γ = 1.63  ±  0.01 (at 1σ c.l.), and the X-ray luminosity was (2.16  ±  0.04)  ×  1034 erg s−1 for a distance of 4 kpc. Based on observations with different instruments, the X-ray luminosity has remained relatively steady over the past ∼15 years. J1109 is spatially associated with the gamma-ray source FL8Y J1109.8−6500, which was detected with Fermi at an average luminosity of (1.5  ±  0.2)  ×  1034 erg s−1 (assuming the distance of J1109) over the 0.1–300 GeV energy band between 2008 and 2016. The source was undetected during ATCA radio observations that were simultaneous with NuSTAR, down to a 3σ flux upper limit of 18 μJy beam−1 (at 7.25 GHz). We show that the phenomenological properties of J1109 point to a binary transitional pulsar candidate currently in a sub-luminous accretion disk state, and that the upper limits derived for the radio emission are consistent with the expected radio luminosity for accreting neutron stars at similar X-ray luminosities.

scholarly journals Discovery and follow-up of ASASSN-19dj: an X-ray and UV luminous TDE in an extreme post-starburst galaxy

2020 ◽  
Vol 500 (2) ◽  
pp. 1673-1696 ◽  
Author(s):  
Jason T Hinkle ◽  
T W-S Holoien ◽  
K Auchettl ◽  
B J Shappee ◽  
J M M Neustadt ◽  
...  
Keyword(s):  
Optical Emission ◽  
Starburst Galaxy ◽  
Late Time ◽  
X Rays ◽  
Tidal Disruption ◽  
X Ray ◽  
Bolometric Luminosity ◽  
Order Of Magnitude ◽  
High Cadence

ABSTRACT We present observations of ASASSN-19dj, a nearby tidal disruption event (TDE) discovered in the post-starburst galaxy KUG 0810+227 by the All-Sky Automated Survey for Supernovae (ASAS-SN) at a distance of d ≃ 98 Mpc. We observed ASASSN-19dj from −21 to 392 d relative to peak ultraviolet (UV)/optical emission using high-cadence, multiwavelength spectroscopy and photometry. From the ASAS-SN g-band data, we determine that the TDE began to brighten on 2019 February 6.8 and for the first 16 d the rise was consistent with a flux ∝t2 power law. ASASSN-19dj peaked in the UV/optical on 2019 March 6.5 (MJD = 58548.5) at a bolometric luminosity of L = (6.2 ± 0.2) × 1044 erg s−1. Initially remaining roughly constant in X-rays and slowly fading in the UV/optical, the X-ray flux increased by over an order of magnitude ∼225 d after peak, resulting from the expansion of the X-ray emitting region. The late-time X-ray emission is well fitted by a blackbody with an effective radius of ∼1 × 1012 cm and a temperature of ∼6 × 105 K. The X-ray hardness ratio becomes softer after brightening and then returns to a harder state as the X-rays fade. Analysis of Catalina Real-Time Transient Survey images reveals a nuclear outburst roughly 14.5 yr earlier with a smooth decline and a luminosity of LV ≥ 1.4 × 1043 erg s−1, although the nature of the flare is unknown. ASASSN-19dj occurred in the most extreme post-starburst galaxy yet to host a TDE, with Lick HδA = 7.67 ± 0.17 Å.

scholarly journals Discovery of a New X-ray Transient in Scorpius GRO J1655-40 ≡ X-ray Nova Scorpii 1994

1996 ◽  
Vol 165 ◽  
pp. 363-367
Author(s):  
W.S. Paciesas ◽  
S.N. Zhang ◽  
B.C. Rubin ◽  
B.A. Harmon ◽  
C.A. Wilson ◽  
...  
Keyword(s):  
Black Hole ◽  
High Resolution ◽  
Power Law ◽  
Radio Observations ◽  
X Ray ◽  
Black Hole Candidate ◽  
Radio Jets ◽  
Transient Source ◽  
Galactic Source ◽  
Photon Index

A bright transient X-ray source, GRO J1655-40 (X-ray Nova Scorpii 1994) was discovered with BATSE (the Burst and Transient Source Experiment) in late July 1994. More recently, the source also became a strong radio emitter, its rise in the radio being approximately anti-correlated with a decline in the hard X-ray intensity. High-resolution radio observations subsequent to this symposium showed evidence for superluminally expanding jets. Since the hard X-ray emission extends to at least 200 keV and we find no evidence of pulsations, we tentatively classify the source as a black-hole candidate. However, its hard X-ray spectrum is unusually steep (power-law photon index α ≃ −3) relative to most other black-hole candidates. In this regard, it resembles GRS 1915+105, the first galactic source to show superluminal radio jets.

DOZ047.79: Bronchoscopic treatment of plastic bronchitis in children

2019 ◽  
Vol 32 (Supplement_1) ◽  
Author(s):  
M Y Erdas ◽  
N Valiyev ◽  
K K Cerit ◽  
Y Gokdemir ◽  
G Kiyan
Keyword(s):  
Respiratory Distress ◽  
Rare Condition ◽  
Airway Disease ◽  
Underlying Disease ◽  
Bronchial Tree ◽  
X Rays ◽  
Plastic Bronchitis ◽  
Left Hemithorax ◽  
X Ray ◽  
Chest X Ray

Abstract Purpose Plastic bronchitis or cast bronchitis is a rare condition characterized by the formation of large gelatinous or rigid airway casts. Classification of plastic bronchitis is done by disease association and cast histology. This rare condition can cause airway obstruction and there is no standardized treatment. Here are presented two cases with plastic bronchitis treated by bronchoscopic removal of casts in our clinic. Patients Case 1: A 9-year-old boy presented with wheezing, cough, and respiratory distress. He expectorated the cast spontaneously and the cast was misdiagnosed as germinative membrane of a hydatid cyst at the previous center. Total collapse of the left hemithorax was seen on chest X-ray. Any underlying disease was not detected. The plastic-like solid structure was detected and easily extracted from the bronchial tree. Pathology results of the casts were eosinophilic mucoid casts. The patient experienced three bronchoscopic removals and had no recurrence thereafter for two years. Case 2: A 7-year-old girl presented with persistent cough and respiratory distress. The patient was referred to our center with the diagnosis of foreign body aspiration. Total collapse of the right middle and lower segment and partial collapse of the upper segment were seen on chest X-ray. Previously, she was diagnosed with reactive airway disease. The plastic-like semisolid structure was detected during bronchoscopy its extraction from the bronchial tree was not easy but was possible. Pathology results were eosinophilic mucoid and fibrinotic casts. This patient still needs bronchoscopy for cast removal after 12 bronchoscopic removals but her symptoms and bronchoscopy findings have regressed with time. Conclusion Bronchoscopic extraction of casts provides fast improvement of patients’ symptoms and postoperative chest X-rays, but recurrence of cast formation is common. Nevertheless, it is the mostly chosen therapy in the literature. Further researches in this area are required.

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