Search Results - "Johnston, Helen M"

Optical properties of high-frequency radio sources from the Australia Telescope 20 GHz (AT20G) Survey by Mahony, Elizabeth K., Sadler, Elaine M., Croom, Scott M., Ekers, Ronald D., Bannister, Keith W., Chhetri, Rajan, Hancock, Paul J., Johnston, Helen M., Massardi, Marcella, Murphy, Tara

“…Our current understanding of radio-loud active galactic nuclei (AGN) comes predominantly from studies at frequencies of 5 GHz and below. With the recent…”
Get full text

The extraordinary radio galaxy MRC B1221–423: probing deeper at radio and optical wavelengths by Johnston, Helen M., Broderick, Jess W., Cotter, Garret, Morganti, Raffaella, Hunstead, Richard W.

“…We present optical spectra and high-resolution multiwavelength radio observations of the compact steep-spectrum radio source MRC B1221−423 (z= 0.1706). MRC…”
Get full text

The nature of the companion star in Circinus X-1 by Johnston, Helen M., Soria, Roberto, Gibson, Joel

“…We present optical spectra and images of the X-ray binary Circinus X-1. The optical light curve of Cir X-1 is strongly variable, changing in brightness by 1.2…”
Get full text

A successful search for intervening 21 cm H i absorption in galaxies at 0.4 < z <1.0 with the Australian square kilometre array pathfinder (ASKAP) by Sadler, Elaine M, Moss, Vanessa A, Allison, James R, Mahony, Elizabeth K, Whiting, Matthew T, Johnston, Helen M, Ellison, Sara L, Lagos, Claudia del P, Koribalski, Bärbel S

“…ABSTRACT We have used the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope to search for intervening 21 cm neutral hydrogen (H i)…”
Get full text

The Large Area Radio Galaxy Evolution Spectroscopic Survey (LARGESS): survey design, data catalogue and GAMA/WiggleZ spectroscopy by Ching, John HY, Sadler, Elaine M, Croom, Scott M, Johnston, Helen M, Pracy, Michael B, Couch, Warrick J, Hopkins, A M, Jurek, Russell J, Pimbblet, K A

“…We present the Large Area Radio Galaxy Evolution Spectroscopic Survey (LARGESS), a spectroscopic catalogue of radio sources designed to include the full range…”
Get full text

Optical properties of high-frequency radio sources from the Australia Telescope 20GHz (AT20G) Survey by Mahony, Elizabeth K, Sadler, Elaine M, Croom, Scott M, Ekers, Ronald D, Bannister, Keith W, Chhetri, Rajan, Hancock, Paul J, Johnston, Helen M, Massardi, Marcella, Murphy, Tara

“…ABSTRACT Our current understanding of radio-loud active galactic nuclei (AGN) comes predominantly from studies at frequencies of 5GHz and below. With the…”
Get full text

The clustering of radio galaxies at z≃ 0.55 from the 2SLAQ LRG survey by Wake, David A., Croom, Scott M., Sadler, Elaine M., Johnston, Helen M.

“…We examine the clustering properties of low-power radio galaxies at redshift 0.4 < z < 0.8, using data from the 2SLAQ Luminous Red Galaxy (LRG) survey, and…”
Get full text

The γ-ray binary LS 5039: mass and orbit constraints from MOST observations by Sarty, Gordon E., Szalai, Tamás, Kiss, László L., Matthews, Jaymie M., Wu, Kinwah, Kuschnig, Rainer, Guenther, David B., Moffat, Anthony F. J., Rucinski, Slavek M., Sasselov, Dimitar, Weiss, Werner W., Huziak, Richard, Johnston, Helen M., Phillips, Andre, Ashley, Michael C. B.

“…The results of a coordinated space-based photometric and ground-based spectroscopic observing campaign on the enigmatic γ-ray binary LS 5039 are reported. 16 d…”
Get full text

Radio galaxies in the 2SLAQ Luminous Red Galaxy Survey - I. The evolution of low-power radio galaxies to z∼ 0.7 by Sadler, Elaine M., Cannon, Russell D., Mauch, Tom, Hancock, Paul J., Wake, David A., Ross, Nic, Croom, Scott M., Drinkwater, Michael J., Edge, Alastair C., Eisenstein, Daniel, Hopkins, Andrew M., Johnston, Helen M., Nichol, Robert, Pimbblet, Kevin A., De Propris, Roberto, Roseboom, Isaac G., Schneider, Donald P., Shanks, Tom

“…We have combined optical data from the 2dF-SDSS (Sloan Digital Sky Survey) LRG (Luminous Red Galaxy) and QSO (quasi-stellar object) (2SLAQ) redshift survey…”
Get full text

Radio galaxies in the 2SLAQ Luminous Red Galaxy Survey - I. The evolution of low-power radio galaxies to z similar to 0.7 by Sadler, Elaine M, Cannon, Russell D, Mauch, Tom, Hancock, Paul J, Wake, David A, Ross, Nic, Croom, Scott M, Drinkwater, Michael J, Edge, Alastair C, Eisenstein, Daniel, Hopkins, Andrew M, Johnston, Helen M, Nichol, Robert, Pimbblet, Kevin A, De Propris, Roberto, Roseboom, Isaac G, Schneider, Donald P, Shanks, Tom

“…We have combined optical data from the 2dF-SDSS (Sloan Digital Sky Survey) LRG (Luminous Red Galaxy) and QSO (quasi-stellar object) (2SLAQ) redshift survey…”
Get full text

Radio galaxies in the 2SLAQ Luminous Red Galaxy survey – II. The stellar populations of radio-loud and radio-quiet LRGs by Johnston, Helen M., Sadler, Elaine M., Cannon, Russell, Croom, Scott M., Ross, Nicholas P., Schneider, Donald P.

“…We present an analysis of the optical spectra of a volume-limited sample of 375 radio galaxies at redshift 0.4 < z < 0.7 from the 2dF-SDSS (Sloan Digital Sky…”
Get full text

Optical spectroscopy of GX 339-4 during the high—soft and low—hard states — II. Line ionization and emission region by Wu, Kinwah, Soria, Roberto, Hunstead, Richard W., Johnston, Helen M.

“…We have carried out observations of the X-ray transient GX 339-4 during its high—soft and low—hard X-ray spectral states. Our high-resolution spectroscopic…”
Get full text

High-resolution optical and infrared spectroscopic observations of Cir X-1 by Johnston, Helen M., Fender, Robert, Wu, Kinwah

“…We present new optical and infrared (IR) observations of Cir X-1 taken near apastron. Both sets of spectra show asymmetric emission lines. Archival optical…”
Get full text

Optical spectroscopy of GX 339-4 during the high-soft and low-hard states — I by Soria, Roberto, Wu, Kinwah, Johnston, Helen M.

“…We carried out spectroscopic observations of the candidate black hole binary GX 339-4 during its low-hard and high-soft X-ray states. We have found that the…”
Get full text

Interstellar Scintillation and Annual Cycles in the BL Lac Source PKS 1519-273 by Jauncey, David L., Johnston, Helen M., Bignall, Hayley E., Lovell, J.E.J., Kedziora-Chudczer, Lucyna, Tzioumis, A.K., Macquart, Jean-Pierre

“…We have measured annual cycles in the time scales of the rapid, intra-day variability of the total and circularly polarized flux density, of the unusual BL Lac…”
Get full text

A radio-emitting X-ray "bullet" ejected by the Vela supernova by Strom, Richard, Johnston, Helen M, Verbunt, Frank, Aschenbach, Bernd

“…X-ray and radio observations of a feature outside the shock-wave boundary of the Vela supernova remnant, which appears to be an ejected fragment with a wake,…”
Get full text

The extraordinary radio galaxy MRC B1221-423: probing deeper at radio and optical wavelengths by Johnston, Helen M., Broderick, Jess W., Cotter, Garret, Morganti, Raffaella, Hunstead, Richard W.

Get full text

The extraordinary radio galaxy MRC B1221-423: probing deeper at radio and optical wavelengths: The extraordinary radio galaxy MRC B1221-423 by Johnston, Helen M., Broderick, Jess W., Cotter, Garret, Morganti, Raffaella, Hunstead, Richard W.

Get full text

Optical properties of high-frequency radio sources from the Australia Telescope 20 GHz (AT20G) Survey: Optical properties of AT20G sources by Mahony, Elizabeth K., Sadler, Elaine M., Croom, Scott M., Ekers, Ronald D., Bannister, Keith W., Chhetri, Rajan, Hancock, Paul J., Johnston, Helen M., Massardi, Marcella, Murphy, Tara

Get full text

The clustering of radio galaxies at z≃ 0.55 from the 2SLAQ LRG survey by Wake, David A., Croom, Scott M., Sadler, Elaine M., Johnston, Helen M.

Get full text