We discuss the galactic distribution of 450 sources detected by the EUVE satellite that have reli... more We discuss the galactic distribution of 450 sources detected by the EUVE satellite that have reliable distance estimates. Late-type stars dominate the nearby EUV source distribution, whereas the majority of EUV source detections with distances > 100pc are hot white dwarf stars. The galactic distribution of all these sources is non-uniform with number enhancements seen towards the Hyades cluster, in
We present the results of simultaneous optical polarimetry and EUV spectroscopy and photometry of... more We present the results of simultaneous optical polarimetry and EUV spectroscopy and photometry of PQ Gem, a magnetic cataclysmic variable which shows observational properties of the strongly magnetic AM Her class, as well as the weaker field DQ Her stars. The EUV spectrum of PQ Gem is weak, showing continuum blueward of 80 A and a few possible weak emission lines due to Mg, Si, and Ne. The EUV lightcurve has a similar appearence to previous X-ray data obtained for PQ Gem, including a narrow "dip" feature which is modulated with the white dwarf spin period. Observed polarisation variations on the spin period, modelled by a slightly modified version of that used in Potter et al. (1997), matched the optical light curve and linear polarisation curve reasonably well, but not the position angle variation. The EUV properties of PQ Gem can also be understood in the context of this model. Subject headings: Cataclysmic Variables, Magnetic CVs, Stars-individual:PQ Gem -- 3 -- 1. Intr...
We present imaging observation of diffuse FUV emission lines emanating from the Gum Nebula, a lar... more We present imaging observation of diffuse FUV emission lines emanating from the Gum Nebula, a large ionized region 18 degrees in radius centered around (l,b)=(258, -2). Observations covering about 50% of the Gum Nebula have been obtained with the SPEAR (FIMS) instrument, flown aboard the STSAT-1 satellite. Our understanding of this nebula and its origins is incomplete; however, past observations
We spatially resolved 2.2 $\mu$m emission from the classical nova V458 Vul 2007 using Palomar Tes... more We spatially resolved 2.2 $\mu$m emission from the classical nova V458 Vul 2007 using Palomar Testbed Interferometer (PTI) immediately following its discovery on 2007 August 8.54 UT. Simultaneously, we obtained a high resolution spectra of the nova during its early days of explosion. We used several simple morphologies to model the nova's ejecta. Our analysis shows that the emission from the nova can be modeled as a disk at low ellipticity which is consistent to the nova being in the fireball phase at which the outflowing gas is optically thick, confirmed by the presence of strong P-Cygni Balmer lines in the spectra. Combining the expansion velocity derived by H$\alpha$ line with the nova's angular expansion rate measured with interferometry, the distance to the nova is computed. The computed distance is 9.9 -11.1 kpc. The spectra of the nova unveils the quick transition of the system from Fe II to He/N which makes V458 Vul 2007 a hybrid nova.
We present the results of simultaneous optical polarimetry and EUV spectroscopy and photometry of... more We present the results of simultaneous optical polarimetry and EUV spectroscopy and photometry of PQ Gem, a magnetic cataclysmic variable which shows observational properties of the strongly magnetic AM Her class, as well as the weaker field DQ Her stars. The EUV spectrum of PQ Gem is weak, showing continuum blueward of 80 Å and a few possible weak emission lines due to Mg, Si, and Ne. The EUV light curve has a similar appearance to previous X-ray data obtained for PQ Gem, including a narrow "dip" feature that is modulated with the white dwarf spin period. Observed polarization variations on the spin period, modeled by a slightly modified version of that used in Potter et al., matched the optical light curve and linear polarization curve reasonably well, but not the position angle variation. The EUV properties of PQ Gem can also be understood in the context of this model.
UV/EUV and Visible Space Instrumentation for Astronomy II, 2003
Page 1. Performance of the Cosmic Hot Interstellar Plasma Spectrometer Martin M. Sirk , Geoffrey ... more Page 1. Performance of the Cosmic Hot Interstellar Plasma Spectrometer Martin M. Sirk , Geoffrey Gaines , Ellen R. Taylor , Michael Sholl , William Marchant , Richelieu Hemphill , Randy A. Kimble , Timothy Sasseen , Mario Marckwordt , and William Donakowski ...
We present simultaneous EUV and infrared (J, K) observations of the polar HU Aquarii obtained dur... more We present simultaneous EUV and infrared (J, K) observations of the polar HU Aquarii obtained during 1998 August when the star was in a high mass accretion state. EUV and IR light curves and EUV spectra are presented and compared with previous observations. The accretion region on the white dwarf has increased in temperature (124,000 to 240,000 K) and radius (0.04RWD to 0.06RWD) compared with previous EUV observations made during low mass accretion states. The EUV and IR photometric observations are shown to have a similar appearance as a function of orbital phase. The EUV photometry shows rapid changes and provides evidence for mass accretion via blobs. The high-state IR light curves present an asymmetric double-humped shape with J=14.8 and K=14.1. We applied an ellipsoidal model fit to the observations, and the result indicates that the cause of the modulated shape is due to both ellipsoidal variations from the Roche lobe filling secondary star and a complex flux combination probably dominated at all orbital phases by cyclotron emission. The source of maximum cyclotron emission appears to be in the accretion column high above the white dwarf surface.
Monthly Notices of the Royal Astronomical Society, 2001
Multiwavelength monitoring observations of the AM Her system, QS Tel, are presented, the centrepi... more Multiwavelength monitoring observations of the AM Her system, QS Tel, are presented, the centrepiece being a coordinated campaign with the ASCA, EUVE and HST satellites and optical observations on 1996 September 28-29. The star was initially observed in an intermediate brightness, single pole state in 1996 April by ROSAT. However two EUVE snapshots of the system in August found it
We present FUV emission line images at 6 different wavelengths obtained with a diffuse imaging sp... more We present FUV emission line images at 6 different wavelengths obtained with a diffuse imaging spectrometer (SPEAR) and compare them to ROSAT and EUVE FUV maps. Spatial differences in the temperature structure are investigated.
We discuss the galactic distribution of 450 sources detected by the EUVE satellite that have reli... more We discuss the galactic distribution of 450 sources detected by the EUVE satellite that have reliable distance estimates. Late-type stars dominate the nearby EUV source distribution, whereas the majority of EUV source detections with distances > 100pc are hot white dwarf stars. The galactic distribution of all these sources is non-uniform with number enhancements seen towards the Hyades cluster, in
We present the results of simultaneous optical polarimetry and EUV spectroscopy and photometry of... more We present the results of simultaneous optical polarimetry and EUV spectroscopy and photometry of PQ Gem, a magnetic cataclysmic variable which shows observational properties of the strongly magnetic AM Her class, as well as the weaker field DQ Her stars. The EUV spectrum of PQ Gem is weak, showing continuum blueward of 80 A and a few possible weak emission lines due to Mg, Si, and Ne. The EUV lightcurve has a similar appearence to previous X-ray data obtained for PQ Gem, including a narrow "dip" feature which is modulated with the white dwarf spin period. Observed polarisation variations on the spin period, modelled by a slightly modified version of that used in Potter et al. (1997), matched the optical light curve and linear polarisation curve reasonably well, but not the position angle variation. The EUV properties of PQ Gem can also be understood in the context of this model. Subject headings: Cataclysmic Variables, Magnetic CVs, Stars-individual:PQ Gem -- 3 -- 1. Intr...
We present imaging observation of diffuse FUV emission lines emanating from the Gum Nebula, a lar... more We present imaging observation of diffuse FUV emission lines emanating from the Gum Nebula, a large ionized region 18 degrees in radius centered around (l,b)=(258, -2). Observations covering about 50% of the Gum Nebula have been obtained with the SPEAR (FIMS) instrument, flown aboard the STSAT-1 satellite. Our understanding of this nebula and its origins is incomplete; however, past observations
We spatially resolved 2.2 $\mu$m emission from the classical nova V458 Vul 2007 using Palomar Tes... more We spatially resolved 2.2 $\mu$m emission from the classical nova V458 Vul 2007 using Palomar Testbed Interferometer (PTI) immediately following its discovery on 2007 August 8.54 UT. Simultaneously, we obtained a high resolution spectra of the nova during its early days of explosion. We used several simple morphologies to model the nova's ejecta. Our analysis shows that the emission from the nova can be modeled as a disk at low ellipticity which is consistent to the nova being in the fireball phase at which the outflowing gas is optically thick, confirmed by the presence of strong P-Cygni Balmer lines in the spectra. Combining the expansion velocity derived by H$\alpha$ line with the nova's angular expansion rate measured with interferometry, the distance to the nova is computed. The computed distance is 9.9 -11.1 kpc. The spectra of the nova unveils the quick transition of the system from Fe II to He/N which makes V458 Vul 2007 a hybrid nova.
We present the results of simultaneous optical polarimetry and EUV spectroscopy and photometry of... more We present the results of simultaneous optical polarimetry and EUV spectroscopy and photometry of PQ Gem, a magnetic cataclysmic variable which shows observational properties of the strongly magnetic AM Her class, as well as the weaker field DQ Her stars. The EUV spectrum of PQ Gem is weak, showing continuum blueward of 80 Å and a few possible weak emission lines due to Mg, Si, and Ne. The EUV light curve has a similar appearance to previous X-ray data obtained for PQ Gem, including a narrow "dip" feature that is modulated with the white dwarf spin period. Observed polarization variations on the spin period, modeled by a slightly modified version of that used in Potter et al., matched the optical light curve and linear polarization curve reasonably well, but not the position angle variation. The EUV properties of PQ Gem can also be understood in the context of this model.
UV/EUV and Visible Space Instrumentation for Astronomy II, 2003
Page 1. Performance of the Cosmic Hot Interstellar Plasma Spectrometer Martin M. Sirk , Geoffrey ... more Page 1. Performance of the Cosmic Hot Interstellar Plasma Spectrometer Martin M. Sirk , Geoffrey Gaines , Ellen R. Taylor , Michael Sholl , William Marchant , Richelieu Hemphill , Randy A. Kimble , Timothy Sasseen , Mario Marckwordt , and William Donakowski ...
We present simultaneous EUV and infrared (J, K) observations of the polar HU Aquarii obtained dur... more We present simultaneous EUV and infrared (J, K) observations of the polar HU Aquarii obtained during 1998 August when the star was in a high mass accretion state. EUV and IR light curves and EUV spectra are presented and compared with previous observations. The accretion region on the white dwarf has increased in temperature (124,000 to 240,000 K) and radius (0.04RWD to 0.06RWD) compared with previous EUV observations made during low mass accretion states. The EUV and IR photometric observations are shown to have a similar appearance as a function of orbital phase. The EUV photometry shows rapid changes and provides evidence for mass accretion via blobs. The high-state IR light curves present an asymmetric double-humped shape with J=14.8 and K=14.1. We applied an ellipsoidal model fit to the observations, and the result indicates that the cause of the modulated shape is due to both ellipsoidal variations from the Roche lobe filling secondary star and a complex flux combination probably dominated at all orbital phases by cyclotron emission. The source of maximum cyclotron emission appears to be in the accretion column high above the white dwarf surface.
Monthly Notices of the Royal Astronomical Society, 2001
Multiwavelength monitoring observations of the AM Her system, QS Tel, are presented, the centrepi... more Multiwavelength monitoring observations of the AM Her system, QS Tel, are presented, the centrepiece being a coordinated campaign with the ASCA, EUVE and HST satellites and optical observations on 1996 September 28-29. The star was initially observed in an intermediate brightness, single pole state in 1996 April by ROSAT. However two EUVE snapshots of the system in August found it
We present FUV emission line images at 6 different wavelengths obtained with a diffuse imaging sp... more We present FUV emission line images at 6 different wavelengths obtained with a diffuse imaging spectrometer (SPEAR) and compare them to ROSAT and EUVE FUV maps. Spatial differences in the temperature structure are investigated.
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Papers by Martin M Sirk