S. Trushkin - Academia.edu (original) (raw)

Papers by S. Trushkin

Research paper thumbnail of The AGILE monitoring of Cygnus X-3: Transient gamma-ray emission and spectral constraints

Research paper thumbnail of Long-term radio behaviour of GPS sources and candidates

This paper is a summary of the work that our group has done (and recently published in several pa... more This paper is a summary of the work that our group has done (and recently published in several papers) on long-term radio variability of GPS sources. We have studied the long-term (up to 30 years) variability of GPS sources and candidates, with emphasis on the high-frequency radio domain. Our data sets show that only a relatively small number of these sources retain their convex spectra when they are monitored densely and for long periods of time. The current GPS samples are especially contaminated by small, beamed blazar-type sources. Also the remaining population with consistently convex GPS-type spectra seems to be heterogeneous, falling into several subpopulations when their observed properties are used for clustering them through a self-organizing map. c © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1

Research paper thumbnail of 8 X-Ray Spectral Behavior of the Relativistic Jet Source Cygnus X-3

Cyg X-3 is an unusual X-ray binary which shows remarkable correlative behavior between the hard X... more Cyg X-3 is an unusual X-ray binary which shows remarkable correlative behavior between the hard X-ray, soft X-ray, and the radio. We present an analysis of these long term light curves in the context of spectral changes of the system. This analysis will also incorporate a set of pointed RXTE observations made during a period when Cyg X-3 made a transition from a quiescent radio state to a flaring state (including a major flare) and then returned to a quiescent radio state.

Research paper thumbnail of The Anatomy of Major Radio/X-ray Flares in the Enigmatic Microquasar Cygnus X-3

Bulletin of the American Astronomical Society, 2011

Cygnus X-3 exhibits major radio flares/jet ejection events like no other microquasar with radio f... more Cygnus X-3 exhibits major radio flares/jet ejection events like no other microquasar with radio flux densities up to 20 Jy. During these major flares Cygnus X-3 displays a variety of phenomena across the electromagnetic spectrum including specific temporal properties such as gamma-ray flares observed before the onset of major radio flare to quasi-periodic oscillations observed during the major radio flare

Research paper thumbnail of A decade of high-resolution radio observations of

The radio emitting X-ray binary GRS 1915+105 shows a wide variety of X-ray and radio states. We p... more The radio emitting X-ray binary GRS 1915+105 shows a wide variety of X-ray and radio states. We present a decade of monitoring observations, with the RXTE-ASM and the Ryle Telescope, in conjunction with high-resolution radio observations using MERLIN and the VLBA. Linear polarisation at 1.4 and 1.6 GHz has been spatially resolved in the radio jets, on a scale of ∼ 150 mas and at flux densities of a few mJy. Depolarisation of the core occurs during radio flaring, associated with the ejection of relativistic knots of emission. We have identified the ejection at four epochs of X-ray flaring. Assuming no deceleration, proper motions of 16.5 to 27 mas per day have been observed, supporting the hypothesis of a varying angle to the line-of-sight per ejection, perhaps in a precessing jet.

Research paper thumbnail of Monitoring of Microquasars with RATAN-600

Research paper thumbnail of AGILE detection of Cygnus X-3 γ-ray active states during the period mid-2009 / mid-2010

Context. Cygnus X-3 (Cyg X-3) is a well-known microquasar producing v ariable emission at all wav... more Context. Cygnus X-3 (Cyg X-3) is a well-known microquasar producing v ariable emission at all wavelengths. Cyg X-3 is a prominent X-ray binary producing relativistic jets, and studying its high energy emission is crucial for the understanding of the fundamental acceleration processes in accreting compact objects. Aims. Our goal is to study extreme particle acceleration and γ-ray production above 100 MeV during special spectral state of Cyg X3 usually characterized by a low hard X-ray flux and enhanced s oft X-ray states. Methods. We observed Cyg X-3 with the AGILE satellite in extended time int rvals from 2009 Jun.–Jul, and 2009 Nov.–2010 Jul. We report here the results of the AGILE γ-ray monitoring of Cyg X-3 as well as the results from extensi ve multiwavelength campaigns involving radio (RATAN-600, AMI-LA and Metsähovi Radio Ob servatories) and X-ray monitoring data (XTE and Swift). Results. We detect a series of repeated γ-ray flaring activity from Cyg X-3 that correlate with th...

Research paper thumbnail of A Massive Jet-Ejection from SS433

The detection of a massive jet-ejection event from SS433 with RXTE is reported. SS433 in its high... more The detection of a massive jet-ejection event from SS433 with RXTE is reported. SS433 in its high state has been monitored with RXTE from 2001/11/09 (MJD = 52222) to 2001/11/25 (MJD = 52238), following a radio flare on 2001/11/02 (MJD = 52215). An irregular temporal variation with time scales of 100-1000 s appears in the light curve, and the amplitude increases day by day. This is the first detection of such a fast variation from the source. In addition to the fast variations, the daily light curve scatters with a time scale of ~day from 2001/11/17 (MJD = 52230). Following the scatter, another radio flare has been detected on 2001/11/22 (MJD = 52235), which has been obviously formed during the X-ray scatter. This is a preliminary report on a massive jet-ejection event witnessed in X-ray band for the first time.

Research paper thumbnail of Pulse Emission Properties of the Magnetar XTEJ1809-197 During the Flaring Activity in December 2018—April 2019

Research paper thumbnail of Investigating the Mini and Giant Radio Flare Episodes of Cygnus X-3

The Astrophysical Journal

The microquasar Cygnus X-3 underwent a giant radio flare in April 2017, reaching a maximum flux o... more The microquasar Cygnus X-3 underwent a giant radio flare in April 2017, reaching a maximum flux of ∼ 16.5 Jy at 8.5 GHz. We present results from a long monitoring campaign carried out with Medicina at 8.5, 18.6 and 24.1 GHz, in parallel to the Metsähovi radio telescope at 37 GHz, from 4 to 11 April 2017. We observe a spectral steepening from α = 0.2 to 0.5 (with S ν ∝ ν −α) within 6 h around the epoch of the peak maximum of the flare, and rapid changes in the spectral slope in the following days during brief enhanced emission episodes while the general trend of the radio flux density indicated the decay of the giant flare. We further study the radio orbital modulation of Cyg X-3 emission associated with the 2017 giant flare and with six mini-flares observed in 1983, 1985, 1994, 1995, 2002 and 2016. The enhanced emission episodes observed during the decline of the giant flare at 8.5 GHz coincide with the orbital phase φ ∼ 0.5 (orbital inferior conjunction). On the other hand the light curves of the mini-flares observed at 15 − 22 GHz peak at φ ∼ 0, except for the 2016 light curve which is shifted of 0.5 w.r.t. the other ones. We attribute the apparent phase shift to the variable location of the emitting region along the bent jet. This might be explained by the different accretion states of the flaring episodes (the 2016 mini-flare occurred in the hypersoft X-ray state).

Research paper thumbnail of Long Term Radio Monitoring - Why Do We Need It

Research paper thumbnail of Radio variations of Cygnus X-3 (Koljonen+, 2010)

We have analysed, following standard procedures using FTOOLS v6.5, 135 archive RXTE observations ... more We have analysed, following standard procedures using FTOOLS v6.5, 135 archive RXTE observations for the HID. The observations are listed in Table A1 together with exposure times of the Proportional Counter Array (PCA) and High Energy X-ray Timing Experiment (HEXTE) as well as corresponding radio/X-ray states and radio flux during or near the observation in question (maximum of half a

Research paper thumbnail of The Data-Processing Techniques and Results of the Observations of the Extended Sources with the RATAN600 Radio Telescope

Investigations of the region of the galactic plane in the direction l = 194° were carried out. Th... more Investigations of the region of the galactic plane in the direction l = 194° were carried out. The aim was to study a part of the proposed supernova remnant Origem Loop, being one of the most extended and old objects of this type with high spatial resolution and sensitivity. The techniques of measuring, data reduction of extended sources with angular sizes comparable to or wider than the beamwidth of the RATAN-600 radio telescope are suggested in the paper. The flux determination results for PKS 0607+17 are also presented.

Research paper thumbnail of Current Status of Radio Source Databases

We review the history and present status of radio-source catalogue archiving and on-line retrieva... more We review the history and present status of radio-source catalogue archiving and on-line retrieval of radio source data. Large efforts were spent by the first author in collecting and restoring electronic versions of new and old source catalogues. Some 67 catalogues with ~520,000 entries were searchable via the "Einstein On-line Service" (EOLS). When EOLS lost maintenance support in 1994 a group at SAO (Russia) started building software tools to search and cross-identify objects between the major radio catalogues, maintained as the "CATalog supporting System" (CATS) at the Special Astrophysical Observatory (SAO, Russia). The independent efforts in east and west have recently been joined. Almost 400 different source lists with ~2,000,000 entries have been archived (and partly prepared) by us. All 5C and Penticton "P"-surveys and many of the published WSRT survey lists are now available. CATS has been developed by O. Verkhodanov, S. Trushkin, V. Chernenko...

Research paper thumbnail of A bright flaring state of SS433

We report that the super-critical microquasar SS433 is the flaring state at radio waves and the o... more We report that the super-critical microquasar SS433 is the flaring state at radio waves and the optical band and would request for followup observations at all frequencies. In the monitoring program of microquasars with the RATAN-600 radio telescope (Trushkin et al., astro-ph/0611550), the flux densities at 1-22 GHz increased from a quiet optically thin synchrotron spectrum: S_nu[Jy] = 1.05*nu^-0.54[GHz] on 2006 Dec 6.48 (UT) to flaring one: S_nu[Jy] = 2.90*nu^-0.43[GHz] on 2006 Dec 8.47 (MJD54077.47) for the total range of 1-22 GHz.

Research paper thumbnail of A decade of high-resolution radio observations of GRS 1915+105

Monthly Notices of the Royal Astronomical Society, 2010

The radio emitting X-ray binary GRS 1915+105 shows a wide variety of X-ray and radio states. We p... more The radio emitting X-ray binary GRS 1915+105 shows a wide variety of X-ray and radio states. We present a decade of monitoring observations, with the RXTE-ASM and the Ryle Telescope, in conjunction with high-resolution radio observations using MERLIN and the VLBA. Linear polarisation at 1.4 and 1.6 GHz has been spatially resolved in the radio jets, on a scale of ∼ 150 mas and at flux densities of a few mJy. Depolarisation of the core occurs during radio flaring, associated with the ejection of relativistic knots of emission. We have identified the ejection at four epochs of X-ray flaring. Assuming no deceleration, proper motions of 16.5 to 27 mas per day have been observed, supporting the hypothesis of a varying angle to the line-of-sight per ejection, perhaps in a precessing jet.

Research paper thumbnail of The 2005 October Multiwavelength Campaign of GRS 1915+ 105

We report the first results of a large multiwavelength campaign of GRS 1915+105 performed between... more We report the first results of a large multiwavelength campaign of GRS 1915+105 performed between 2005 October 16 to October 18 with Suzaku, INTEGRAL, RXTE, Swift, Spitzer, and ground observatories including Subaru, ESO/NTT, REM (infrared), VLA, ATCA, Nancay, Ryle, and RATAN (radio). GRS 1915+105 was firstly in the stable state with a 6 Hz QPO but then entered into the oscillation phase identified as Class θ. The Suzaku spectra in the 1-80 keV band are very soft, approximated by a photo index of 3-3.8 with varying iron-K features in different Xray states. The simultaneous Subaru and X-ray light curves in the oscillation phase indicate that infrared flares occur after the X-ray dip with variable time delay. This result strongly suggests that the disc transition from State C to State A triggers the ejection of jet, which eventually produces infrared/radio flares by internal shock.

Research paper thumbnail of Photoionization Emission Models for the Cyg X-3 X-Ray Spectrum

The Astrophysical Journal

We present model fits to the X-ray line spectrum of the well known High Mass X-ray binary Cyg X-3... more We present model fits to the X-ray line spectrum of the well known High Mass X-ray binary Cyg X-3. The primary observational dataset is a spectrum taken with the Chandra X-ray Observatory High Energy Transmission Grating (HETG) in 2006, though we compare it to all the other observations of this source taken so far by this instrument. We show that the density must be ≥ 10 12 cm −3 in the region responsible for most of the emission. We discuss the influence of the dust scattering halo on the broad band spectrum and we argue that dust scattering and extinction is not the most likely origin for the narrow feature seen near the Si K edge. We identify the features of a wind in the profiles of the strong resonance lines and we show that the wind is more apparent in the lines from the lighter elements. We argue that this wind is most likely associated with the companion star. We show that the intensities of most lines can be fitted, crudely, by a single component photoionized model. However, the iron K lines do not fit with this model. We show that the iron K line variability as a function of orbital phase is different from the lower energy lines, which indicates that the lines arise in physically distinct regions. We discuss the interpretation of these results in the context of what is known about the system and similar systems.

Research paper thumbnail of Low Frequency Catalogues of the CATS Database

Symposium - International Astronomical Union

We describe the most complete, publicly accessible database of radio sources, CATS (“astrophysica... more We describe the most complete, publicly accessible database of radio sources, CATS (“astrophysical CATalogues Support system”). It contains more than 300 catalogues of objects detected in various (mostly radio) wavelength ranges. Apart from catalogues drawn from the most important existing surveys and compilations (e.g. NVSS, FIRST, GB6, IRAS, ROSAT, PGC, MCG), CATS includes the largest low-frequency catalogues published so far: UTR, Culgoora, Cambridge, Miyun, WENSS, TXS, Bologna and Molonglo etc., CATS allows one to operate with these, and to draw samples of objects for the study of a large variety of astrophysical problems. Some modes of access are described here.

Research paper thumbnail of An alternative catalogue collection and a system to exploit it: CATS

Conceived in 1996 to support observations with the RATAN-600 radio telescope, CATS is now a publi... more Conceived in 1996 to support observations with the RATAN-600 radio telescope, CATS is now a publicly accessible database allowing to search through 400 catalogs, all of them accessible by anonymous ftp, with a total of 109 records (). CATS' content overlaps only partly with that of VizieR at CDS and is more complete for radio sources due to contributions from

Research paper thumbnail of The AGILE monitoring of Cygnus X-3: Transient gamma-ray emission and spectral constraints

Research paper thumbnail of Long-term radio behaviour of GPS sources and candidates

This paper is a summary of the work that our group has done (and recently published in several pa... more This paper is a summary of the work that our group has done (and recently published in several papers) on long-term radio variability of GPS sources. We have studied the long-term (up to 30 years) variability of GPS sources and candidates, with emphasis on the high-frequency radio domain. Our data sets show that only a relatively small number of these sources retain their convex spectra when they are monitored densely and for long periods of time. The current GPS samples are especially contaminated by small, beamed blazar-type sources. Also the remaining population with consistently convex GPS-type spectra seems to be heterogeneous, falling into several subpopulations when their observed properties are used for clustering them through a self-organizing map. c © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1

Research paper thumbnail of 8 X-Ray Spectral Behavior of the Relativistic Jet Source Cygnus X-3

Cyg X-3 is an unusual X-ray binary which shows remarkable correlative behavior between the hard X... more Cyg X-3 is an unusual X-ray binary which shows remarkable correlative behavior between the hard X-ray, soft X-ray, and the radio. We present an analysis of these long term light curves in the context of spectral changes of the system. This analysis will also incorporate a set of pointed RXTE observations made during a period when Cyg X-3 made a transition from a quiescent radio state to a flaring state (including a major flare) and then returned to a quiescent radio state.

Research paper thumbnail of The Anatomy of Major Radio/X-ray Flares in the Enigmatic Microquasar Cygnus X-3

Bulletin of the American Astronomical Society, 2011

Cygnus X-3 exhibits major radio flares/jet ejection events like no other microquasar with radio f... more Cygnus X-3 exhibits major radio flares/jet ejection events like no other microquasar with radio flux densities up to 20 Jy. During these major flares Cygnus X-3 displays a variety of phenomena across the electromagnetic spectrum including specific temporal properties such as gamma-ray flares observed before the onset of major radio flare to quasi-periodic oscillations observed during the major radio flare

Research paper thumbnail of A decade of high-resolution radio observations of

The radio emitting X-ray binary GRS 1915+105 shows a wide variety of X-ray and radio states. We p... more The radio emitting X-ray binary GRS 1915+105 shows a wide variety of X-ray and radio states. We present a decade of monitoring observations, with the RXTE-ASM and the Ryle Telescope, in conjunction with high-resolution radio observations using MERLIN and the VLBA. Linear polarisation at 1.4 and 1.6 GHz has been spatially resolved in the radio jets, on a scale of ∼ 150 mas and at flux densities of a few mJy. Depolarisation of the core occurs during radio flaring, associated with the ejection of relativistic knots of emission. We have identified the ejection at four epochs of X-ray flaring. Assuming no deceleration, proper motions of 16.5 to 27 mas per day have been observed, supporting the hypothesis of a varying angle to the line-of-sight per ejection, perhaps in a precessing jet.

Research paper thumbnail of Monitoring of Microquasars with RATAN-600

Research paper thumbnail of AGILE detection of Cygnus X-3 γ-ray active states during the period mid-2009 / mid-2010

Context. Cygnus X-3 (Cyg X-3) is a well-known microquasar producing v ariable emission at all wav... more Context. Cygnus X-3 (Cyg X-3) is a well-known microquasar producing v ariable emission at all wavelengths. Cyg X-3 is a prominent X-ray binary producing relativistic jets, and studying its high energy emission is crucial for the understanding of the fundamental acceleration processes in accreting compact objects. Aims. Our goal is to study extreme particle acceleration and γ-ray production above 100 MeV during special spectral state of Cyg X3 usually characterized by a low hard X-ray flux and enhanced s oft X-ray states. Methods. We observed Cyg X-3 with the AGILE satellite in extended time int rvals from 2009 Jun.–Jul, and 2009 Nov.–2010 Jul. We report here the results of the AGILE γ-ray monitoring of Cyg X-3 as well as the results from extensi ve multiwavelength campaigns involving radio (RATAN-600, AMI-LA and Metsähovi Radio Ob servatories) and X-ray monitoring data (XTE and Swift). Results. We detect a series of repeated γ-ray flaring activity from Cyg X-3 that correlate with th...

Research paper thumbnail of A Massive Jet-Ejection from SS433

The detection of a massive jet-ejection event from SS433 with RXTE is reported. SS433 in its high... more The detection of a massive jet-ejection event from SS433 with RXTE is reported. SS433 in its high state has been monitored with RXTE from 2001/11/09 (MJD = 52222) to 2001/11/25 (MJD = 52238), following a radio flare on 2001/11/02 (MJD = 52215). An irregular temporal variation with time scales of 100-1000 s appears in the light curve, and the amplitude increases day by day. This is the first detection of such a fast variation from the source. In addition to the fast variations, the daily light curve scatters with a time scale of ~day from 2001/11/17 (MJD = 52230). Following the scatter, another radio flare has been detected on 2001/11/22 (MJD = 52235), which has been obviously formed during the X-ray scatter. This is a preliminary report on a massive jet-ejection event witnessed in X-ray band for the first time.

Research paper thumbnail of Pulse Emission Properties of the Magnetar XTEJ1809-197 During the Flaring Activity in December 2018—April 2019

Research paper thumbnail of Investigating the Mini and Giant Radio Flare Episodes of Cygnus X-3

The Astrophysical Journal

The microquasar Cygnus X-3 underwent a giant radio flare in April 2017, reaching a maximum flux o... more The microquasar Cygnus X-3 underwent a giant radio flare in April 2017, reaching a maximum flux of ∼ 16.5 Jy at 8.5 GHz. We present results from a long monitoring campaign carried out with Medicina at 8.5, 18.6 and 24.1 GHz, in parallel to the Metsähovi radio telescope at 37 GHz, from 4 to 11 April 2017. We observe a spectral steepening from α = 0.2 to 0.5 (with S ν ∝ ν −α) within 6 h around the epoch of the peak maximum of the flare, and rapid changes in the spectral slope in the following days during brief enhanced emission episodes while the general trend of the radio flux density indicated the decay of the giant flare. We further study the radio orbital modulation of Cyg X-3 emission associated with the 2017 giant flare and with six mini-flares observed in 1983, 1985, 1994, 1995, 2002 and 2016. The enhanced emission episodes observed during the decline of the giant flare at 8.5 GHz coincide with the orbital phase φ ∼ 0.5 (orbital inferior conjunction). On the other hand the light curves of the mini-flares observed at 15 − 22 GHz peak at φ ∼ 0, except for the 2016 light curve which is shifted of 0.5 w.r.t. the other ones. We attribute the apparent phase shift to the variable location of the emitting region along the bent jet. This might be explained by the different accretion states of the flaring episodes (the 2016 mini-flare occurred in the hypersoft X-ray state).

Research paper thumbnail of Long Term Radio Monitoring - Why Do We Need It

Research paper thumbnail of Radio variations of Cygnus X-3 (Koljonen+, 2010)

We have analysed, following standard procedures using FTOOLS v6.5, 135 archive RXTE observations ... more We have analysed, following standard procedures using FTOOLS v6.5, 135 archive RXTE observations for the HID. The observations are listed in Table A1 together with exposure times of the Proportional Counter Array (PCA) and High Energy X-ray Timing Experiment (HEXTE) as well as corresponding radio/X-ray states and radio flux during or near the observation in question (maximum of half a

Research paper thumbnail of The Data-Processing Techniques and Results of the Observations of the Extended Sources with the RATAN600 Radio Telescope

Investigations of the region of the galactic plane in the direction l = 194° were carried out. Th... more Investigations of the region of the galactic plane in the direction l = 194° were carried out. The aim was to study a part of the proposed supernova remnant Origem Loop, being one of the most extended and old objects of this type with high spatial resolution and sensitivity. The techniques of measuring, data reduction of extended sources with angular sizes comparable to or wider than the beamwidth of the RATAN-600 radio telescope are suggested in the paper. The flux determination results for PKS 0607+17 are also presented.

Research paper thumbnail of Current Status of Radio Source Databases

We review the history and present status of radio-source catalogue archiving and on-line retrieva... more We review the history and present status of radio-source catalogue archiving and on-line retrieval of radio source data. Large efforts were spent by the first author in collecting and restoring electronic versions of new and old source catalogues. Some 67 catalogues with ~520,000 entries were searchable via the "Einstein On-line Service" (EOLS). When EOLS lost maintenance support in 1994 a group at SAO (Russia) started building software tools to search and cross-identify objects between the major radio catalogues, maintained as the "CATalog supporting System" (CATS) at the Special Astrophysical Observatory (SAO, Russia). The independent efforts in east and west have recently been joined. Almost 400 different source lists with ~2,000,000 entries have been archived (and partly prepared) by us. All 5C and Penticton "P"-surveys and many of the published WSRT survey lists are now available. CATS has been developed by O. Verkhodanov, S. Trushkin, V. Chernenko...

Research paper thumbnail of A bright flaring state of SS433

We report that the super-critical microquasar SS433 is the flaring state at radio waves and the o... more We report that the super-critical microquasar SS433 is the flaring state at radio waves and the optical band and would request for followup observations at all frequencies. In the monitoring program of microquasars with the RATAN-600 radio telescope (Trushkin et al., astro-ph/0611550), the flux densities at 1-22 GHz increased from a quiet optically thin synchrotron spectrum: S_nu[Jy] = 1.05*nu^-0.54[GHz] on 2006 Dec 6.48 (UT) to flaring one: S_nu[Jy] = 2.90*nu^-0.43[GHz] on 2006 Dec 8.47 (MJD54077.47) for the total range of 1-22 GHz.

Research paper thumbnail of A decade of high-resolution radio observations of GRS 1915+105

Monthly Notices of the Royal Astronomical Society, 2010

The radio emitting X-ray binary GRS 1915+105 shows a wide variety of X-ray and radio states. We p... more The radio emitting X-ray binary GRS 1915+105 shows a wide variety of X-ray and radio states. We present a decade of monitoring observations, with the RXTE-ASM and the Ryle Telescope, in conjunction with high-resolution radio observations using MERLIN and the VLBA. Linear polarisation at 1.4 and 1.6 GHz has been spatially resolved in the radio jets, on a scale of ∼ 150 mas and at flux densities of a few mJy. Depolarisation of the core occurs during radio flaring, associated with the ejection of relativistic knots of emission. We have identified the ejection at four epochs of X-ray flaring. Assuming no deceleration, proper motions of 16.5 to 27 mas per day have been observed, supporting the hypothesis of a varying angle to the line-of-sight per ejection, perhaps in a precessing jet.

Research paper thumbnail of The 2005 October Multiwavelength Campaign of GRS 1915+ 105

We report the first results of a large multiwavelength campaign of GRS 1915+105 performed between... more We report the first results of a large multiwavelength campaign of GRS 1915+105 performed between 2005 October 16 to October 18 with Suzaku, INTEGRAL, RXTE, Swift, Spitzer, and ground observatories including Subaru, ESO/NTT, REM (infrared), VLA, ATCA, Nancay, Ryle, and RATAN (radio). GRS 1915+105 was firstly in the stable state with a 6 Hz QPO but then entered into the oscillation phase identified as Class θ. The Suzaku spectra in the 1-80 keV band are very soft, approximated by a photo index of 3-3.8 with varying iron-K features in different Xray states. The simultaneous Subaru and X-ray light curves in the oscillation phase indicate that infrared flares occur after the X-ray dip with variable time delay. This result strongly suggests that the disc transition from State C to State A triggers the ejection of jet, which eventually produces infrared/radio flares by internal shock.

Research paper thumbnail of Photoionization Emission Models for the Cyg X-3 X-Ray Spectrum

The Astrophysical Journal

We present model fits to the X-ray line spectrum of the well known High Mass X-ray binary Cyg X-3... more We present model fits to the X-ray line spectrum of the well known High Mass X-ray binary Cyg X-3. The primary observational dataset is a spectrum taken with the Chandra X-ray Observatory High Energy Transmission Grating (HETG) in 2006, though we compare it to all the other observations of this source taken so far by this instrument. We show that the density must be ≥ 10 12 cm −3 in the region responsible for most of the emission. We discuss the influence of the dust scattering halo on the broad band spectrum and we argue that dust scattering and extinction is not the most likely origin for the narrow feature seen near the Si K edge. We identify the features of a wind in the profiles of the strong resonance lines and we show that the wind is more apparent in the lines from the lighter elements. We argue that this wind is most likely associated with the companion star. We show that the intensities of most lines can be fitted, crudely, by a single component photoionized model. However, the iron K lines do not fit with this model. We show that the iron K line variability as a function of orbital phase is different from the lower energy lines, which indicates that the lines arise in physically distinct regions. We discuss the interpretation of these results in the context of what is known about the system and similar systems.

Research paper thumbnail of Low Frequency Catalogues of the CATS Database

Symposium - International Astronomical Union

We describe the most complete, publicly accessible database of radio sources, CATS (“astrophysica... more We describe the most complete, publicly accessible database of radio sources, CATS (“astrophysical CATalogues Support system”). It contains more than 300 catalogues of objects detected in various (mostly radio) wavelength ranges. Apart from catalogues drawn from the most important existing surveys and compilations (e.g. NVSS, FIRST, GB6, IRAS, ROSAT, PGC, MCG), CATS includes the largest low-frequency catalogues published so far: UTR, Culgoora, Cambridge, Miyun, WENSS, TXS, Bologna and Molonglo etc., CATS allows one to operate with these, and to draw samples of objects for the study of a large variety of astrophysical problems. Some modes of access are described here.

Research paper thumbnail of An alternative catalogue collection and a system to exploit it: CATS

Conceived in 1996 to support observations with the RATAN-600 radio telescope, CATS is now a publi... more Conceived in 1996 to support observations with the RATAN-600 radio telescope, CATS is now a publicly accessible database allowing to search through 400 catalogs, all of them accessible by anonymous ftp, with a total of 109 records (). CATS' content overlaps only partly with that of VizieR at CDS and is more complete for radio sources due to contributions from