Staff profile

Research Interests (Astronomy)

My research focuses on the study of interacting binaries. These are systems that are comprised a compact object (Black Hole, Neutron Star or White Dwarf) in a close binary orbit with a (usually) less evolved star. I use the variability of the light emitted from such sources to probe the different components of the binary (the donor star, accretion disk, compact object and out-flowing jet). This involves observing the sources at a number of wavelengths to probe the different regions. These include X-rays (RXTE, SWIFT and XMM), Optical/UV (VLT, Keck, WHT, Palomar 200-inch and HST) and Infra-red (VLT) observations. I combine these observations to indirectly image the systems in order to better understand the interactions of light and matter in these extreme physical environments.

Research Interests (Instrumentation)

My research focuses on the development of instrumenation based around Kinetic Inductance Detectors (KIDs). These are superconducting detectors that are capable of measuring the arrival time of individual optical/near-IR photons to ~1microsecond and simultaneously measuring their energy to ~5-10%. I am working with teams in Europe and the US to develop uniquely powerful instruments based around arrays of 1000's of such devices.

• Centre for Advanced Instrumentation

Conference Paper

• Calcines Rosario, A. Z., Wells, M., O’Brien, K. S., Morris, S. L., Seifert, W., Zanutta, A., Evans, C., & Di Marcantonio, P. (2022, December). CUBES: application of image slicers to reformat the field for two spectral resolving powers. Presented at Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation V
• Thatte, N. A., Clarke, F., Bryson, I., Shnetler, H., Tecza, M., Fusco, T., Bacon, R. M., Richard, J., Mediavilla, E., Neichel, B., Arribas, S., Garcia-Lorenzo, B., Remillieux, A., El Madi, K., Herreros, J. M., Melotte, D., O'Brien, K., Tosh, I. A., Vernet, J., Hammersley, P., …Evans, C. J. (2016, December). The E-ELT first light spectrograph HARMONI: capabilities and modes. Presented at Ground-based and Airborne Instrumentation for Astronomy VI,: SPIE Astronomical Telescopes + Instrumentation, 2016, Edinburgh

Journal Article

• Igl, A. B., Hynes, R. I., O’Brien, K. S., Robinson, E. L., & Britt, C. T. (2024). Links between optical and X-ray light in Cygnus X-2. Monthly Notices of the Royal Astronomical Society, 532(1), 241-258. https://doi.org/10.1093/mnras/stae1262
• Igl, A. B., Hynes, R. I., Britt, C. T., O’Brien, K. S., & Mikles, V. J. (2023). Links between optical and X-ray light in Scorpius X-1. Monthly Notices of the Royal Astronomical Society, 526(1), 645–660. https://doi.org/10.1093/mnras/stad2721
• Vincentelli, F. M., Casella, P., Borghese, A., Cavecchi, Y., Mastroserio, G., Stella, L., Altamirano, D., Padilla, M. A., Baglio, M. C., Belloni, T. M., Casares, J., Cúneo, V. A., Degenaar, N., Trigo, M. D., Fender, R., Maccarone, T., Malzac, J., Sánchez, D. M., Middleton, M., Migliari, S., …Uttley, P. (2023). Sub-second infrared variability from the archetypal accreting neutron star 4U 1728−34. Monthly Notices of the Royal Astronomical Society, 525(2), 2509-2518. https://doi.org/10.1093/mnras/stad2414
• Calcines, A., Wells, M., O’Brien, K., Morris, S., Seifert, W., Zanutta, A., Evans, C., & Di Marcantonio, P. (2023). Design of the VLT-CUBES image slicers: Field re-formatters to provide two spectral resolutions. Experimental Astronomy, 55(1), 267-280. https://doi.org/10.1007/s10686-022-09866-5
• Vincentelli, F., Casella, P., Russell, D., Baglio, M., Veledina, A., Maccarone, T., Malzac, J., Fender, R., O’Brien, K., & Uttley, P. (2021). Fast infrared variability from the black hole candidate MAXI J1535−571 and tight constraints on the modelling. Monthly Notices of the Royal Astronomical Society, 503(1), 614-624. https://doi.org/10.1093/mnras/stab475
• Dodkins, R. H., Davis, K. K., Lewis, B., Mahashabde, S., Mazin, B. A., Lipartito, I. A., Fruitwala, N., O’Brien, K., & Thatte, N. (2020). First Principle Simulator of a Stochastically Varying Image Plane for Photon-counting High Contrast Applications. Publications of the Astronomical Society of the Pacific, 132(1016), Article 104503. https://doi.org/10.1088/1538-3873/aba9e4
• O’Brien, K. (2020). KIDSpec: An MKID-Based Medium-Resolution, Integral Field Spectrograph. Journal of Low Temperature Physics, 199(1-2), 537-546. https://doi.org/10.1007/s10909-020-02347-z
• Vincentelli, F., Casella, P., Petrucci, P., Maccarone, T., Russell, D., Uttley, P., Marco, B. D., Fender, R., Gandhi, P., Malzac, J., O’Brien, K., & Tomsick, J. (2019). Physical Constraints from Near-infrared Fast Photometry of the Black Hole Transient GX 339–4. Astrophysical Journal Letters, 887(1), Article L19. https://doi.org/10.3847/2041-8213/ab5860
• Cristina Baglio, M., Russell, D. M., Casella, P., Al Noori, H., Al Yazeedi, A., Belloni, T., Buckley, D. A., Cadolle Bel, M., Ceccobello, C., Corbel, S., Coti Zelati, F., Díaz Trigo, M., Fender, R. P., Gallo, E., Gandhi, P., Homan, J., Koljonen, K. I., Lewis, F., Maccarone, T. J., Malzac, J., …Vincentelli, F. M. (2018). A Wildly Flickering Jet in the Black Hole X-Ray Binary MAXI J1535–571. Astrophysical Journal, 867(2), Article 114. https://doi.org/10.3847/1538-4357/aae532
• Malzac, J., Kalamkar, M., Vincentelli, F., Vue, A., Drappeau, S., Belmont, R., Casella, P., Clavel, M., Corbel, S., Coriat, M., Dornic, D., Ferreira, J., Henri, G., Maccarone, T. J., Marcowith, A., O’Brien, K., Péault, M., Petrucci, P.-O., Rodriguez, J., Russell, D. M., & Uttley, P. (2018). A jet model for the fast IR variability of the black hole X-ray binary GX 339-4. Monthly Notices of the Royal Astronomical Society, 480(2), 2054-2071. https://doi.org/10.1093/mnras/sty2006
• Vincentelli, F., Casella, P., Maccarone, T., Uttley, P., Gandhi, P., Belloni, T., De Marco, B., Russell, D., Stella, L., & O'Brien, K. (2018). Characterization of the infrared/X-ray subsecond variability for the black hole transient GX 339-4. Monthly Notices of the Royal Astronomical Society, 477(4), 4524-4533. https://doi.org/10.1093/mnras/sty710
• Dodkins, R., Mahashabde, S., O’Brien, K., Thatte, N., Fruitwala, N., Walter, A., Meeker, S., Szypryt, P., & Mazin, B. (2018). MKID digital readout tuning with deep learning. Astronomy and computing, 23, 60-71. https://doi.org/10.1016/j.ascom.2018.03.001
• Wang, L., Steeghs, D., Casares, J., Charles, P., Muñoz-Darias, T., Marsh, T., Hynes, R., & O'Brien, K. (2017). System mass constraints for the accreting millisecond pulsar XTE J1814-338 using Bowen fluorescence. Monthly Notices of the Royal Astronomical Society, 466(2), 2261-2271. https://doi.org/10.1093/mnras/stw3312
• Kalamkar, M., Casella, P., Uttley, P., O'Brien, K., Russell, D., Maccarone, T., van der Klis, M., & Vincentelli, F. (2016). Detection of the first infra-red quasi-periodic oscillation in a black hole X-ray binary. Monthly Notices of the Royal Astronomical Society, 460(3), 3284-3291. https://doi.org/10.1093/mnras/stw1211
• Kendrew, S., Zieleniewski, S., Houghton, R., Thatte, N., Devriendt, J., Tecza, M., Clarke, F., O'Brien, K., & Häußler, B. (2016). Simulated stellar kinematics studies of high-redshift galaxies with the HARMONI Integral Field Spectrograph. Monthly Notices of the Royal Astronomical Society, 458(3), 2405-2422. https://doi.org/10.1093/mnras/stw438
• Dhillon, V., Marsh, T., Atkinson, D., Bezawada, N., Bours, M., Copperwheat, C., Gamble, T., Hardy, L., Hickman, R., Irawati, P., Ives, D., Kerry, P., Leckngam, A., Littlefair, S., McLay, S., O'Brien, K., Peacocke, P., Poshyachinda, S., Richichi, A., Soonthornthum, B., & Vick, A. (2015). Erratum: ULTRASPEC: a high-speed imaging photometer on the 2.4-m Thai National Telescope. Monthly Notices of the Royal Astronomical Society, 446,
• van Eyken, J., Strader, M., Walter, A., Meeker, S., Szypryt, P., Stoughton, C., O'Brien, K., Marsden, D., Rice, N., Lin, Y., & Mazin, B. (2015). The ARCONS Pipeline: Data Reduction for MKID Arrays. Astrophysical Journal Supplement, 219,
• Gandhi, P., Shaw, A., Pahari, M., Littlefair, S., Hardy, L., Dhillon, V., Marsh, T., Casella, P., Charles, P., Done, C., Russell, D., Shahbaz, T., Casares, J., Munoz-Darias, T., Tomsick, J., O'Brien, K., Kuulkers, E., Altamirano, D., Knigge, C., Motta, S., & Walton, D. (2015). Correlated Optical and X-ray variability in V404 Cyg
• Szypryt, P., Duggan, G., Mazin, B., Meeker, S., Strader, M., van Eyken, J., Marsden, D., O'Brien, K., Walter, A., Ulbricht, G., Prince, T., Stoughton, C., & Bumble, B. (2014). Direct detection of SDSS J0926+3624 orbital expansion with ARCONS. Monthly Notices of the Royal Astronomical Society, 439(3), 2765-2770. https://doi.org/10.1093/mnras/stu137
• Dhillon, V., Marsh, T., Atkinson, D., Bezawada, N., Bours, M., Copperwheat, C., Gamble, T., Hardy, L., Hickman, R., Irawati, P., Ives, D., Kerry, P., Leckngam, A., Littlefair, S., McLay, S., O'Brien, K., Peacocke, P., Poshyachinda, S., Richichi, A., Soonthornthum, B., & Vick, A. (2014). ULTRASPEC: a high-speed imaging photometer on the 2.4-m Thai National Telescope. Monthly Notices of the Royal Astronomical Society, 444, 4009-4021
• Russell, D., Russell, T., Miller-Jones, J., O'Brien, K., Soria, R., Sivakoff, G., Slaven-Blair, T., Lewis, F., Markoff, S., Homan, J., Altamirano, D., Curran, P., Rupen, M., Belloni, T., Cadolle Bel, M., Casella, P., Corbel, S., Dhawan, V., Fender, R., Gallo, E., …Tudose, V. (2013). An Evolving Compact Jet in the Black Hole X-Ray Binary MAXI J1836-194. Astrophysical Journal, 768,
• Strader, M., Johnson, M., Mazin, B., Spiro Jaeger, G., Gwinn, C., Meeker, S., Szypryt, P., van Eyken, J., Marsden, D., O'Brien, K., Walter, A., Ulbricht, G., Stoughton, C., & Bumble, B. (2013). Excess Optical Enhancement Observed with ARCONS for Early Crab Giant Pulses. Astrophysical Journal, 779,
• Marsden, D. W., Mazin, B. A., O'Brien, K., & Hirata, C. (2013). Giga-z: A 100,000 Object Superconducting Spectrophotometer for LSST Follow-up. Astrophysical Journal Supplement, 208,
• Russell, D., Markoff, S., Casella, P., Cantrell, A., Chatterjee, R., Fender, R., Gallo, E., Gandhi, P., Homan, J., Maitra, D., Miller-Jones, J., O'Brien, K., & Shahbaz, T. (2013). Jet spectral breaks in black hole X-ray binaries. Monthly Notices of the Royal Astronomical Society, 429, 815-832
• Mazin, B., Meeker, S., Strader, M., Szypryt, P., Marsden, D., van Eyken, J., Duggan, G., Walter, A., Ulbricht, G., Johnson, M., Bumble, B., O'Brien, K., & Stoughton, C. (2013). ARCONS: A 2024 Pixel Optical through Near-IR Cryogenic Imaging Spectrophotometer. Publications of the Astronomical Society of the Pacific, 125,
• Mazin, B. A., Bumble, B., Meeker, S. R., O'Brien, K., McHugh, S., & Langman, E. (2012). A superconducting focal plane array for ultraviolet, optical, and near-infrared astrophysics. Optics Express, 20,
• Cornelisse, R., D'Avanzo, P., Campana, S., Casares, J., Charles, P., Israel, G., Muñoz-Darias, T., O'Brien, K., Steeghs, D., Stella, L., & Torres, M. (2012). The nature of the X-ray transient MAXI J0556-332. Monthly Notices of the Royal Astronomical Society, 420, 3538-3544
• Russell, D., Curran, P., Muñoz-Darias, T., Lewis, F., Motta, S., Stiele, H., Belloni, T., Miller-Jones, J., Jonker, P., O'Brien, K., Homan, J., Casella, P., Gandhi, P., Soleri, P., Markoff, S., Maitra, D., Gallo, E., & Cadolle Bel, M. (2012). A late jet rebrightening revealed from multiwavelength monitoring of the black hole candidate XTE J1752-223. Monthly Notices of the Royal Astronomical Society, 419, 1740-1751
• Russell, D., O'Brien, K., Muñoz-Darias, T., Casella, P., Gandhi, P., & Revnivtsev, M. (2012). The near-infrared counterpart of 4U 1636-53. Astronomy and Astrophysics, 539,
• McHugh, S., Mazin, B. A., Serfass, B., Meeker, S., O'Brien, K., Duan, R., Raffanti, R., & Werthimer, D. (2012). A readout for large arrays of microwave kinetic inductance detectors. Review of Scientific Instruments, 83,
• Patat, F., Moehler, S., O'Brien, K., Pompei, E., Bensby, T., Carraro, G., de Ugarte Postigo, A., Fox, A., Gavignaud, I., James, G., Korhonen, H., Ledoux, C., Randall, S., Sana, H., Smoker, J., Stefl, S., & Szeifert, T. (2011). Optical atmospheric extinction over Cerro Paranal. Astronomy and Astrophysics, 527,
• Russell, D., Belloni, T., Miller-Jones, J., O'Brien, K., Gandhi, P., Cadolle Bel, M., Markoff, S., Casella, P., Homan, J., Gallo, E., Fender, R., Shahbaz, T., & Corbel, S. (2011). Bright mid-infrared detections of MAXI J1836-194 with VISIR on the VLT: brightening of the compact jet
• Durant, M., Shahbaz, T., Gandhi, P., Cornelisse, R., Muñoz-Darias, T., Casares, J., Dhillon, V., Marsh, T., Spruit, H., O'Brien, K., Steeghs, D., & Hynes, R. (2011). High time resolution optical/X-ray cross-correlations for X-ray binaries: anticorrelations and rapid variability. Monthly Notices of the Royal Astronomical Society, 410, 2329-2338
• Moehler, S., Freudling, W., Møller, P., Patat, F., Rupprecht, G., & O'Brien, K. (2010). Correction of Field Rotator-Induced Flat-Field Systematics--A Case Study Using Archived VLT-FORS Data. Publications of the Astronomical Society of the Pacific, 122,
• Casella, P., Maccarone, T., O'Brien, K., Fender, R., Russell, D., van der Klis, M., Pe'Er, A., Maitra, D., Altamirano, D., Belloni, T., Kanbach, G., Klein-Wolt, M., Mason, E., Soleri, P., Stefanescu, A., Wiersema, K., & Wijnands, R. (2010). Fast infrared variability from a relativistic jet in GX 339-4. Monthly Notices of the Royal Astronomical Society, 404, L21-L25
• O'Brien, K. (2009). FORS in the Era of Second Generation VLT Instrumentation
• Muñoz-Darias, T., Casares, J., O'Brien, K., Steeghs, D., Martínez-Pais, I., Cornelisse, R., & Charles, P. (2009). Dynamical constraints on the neutron star mass in EXO 0748-676. Monthly Notices of the Royal Astronomical Society, 394, L136-L140
• Shahbaz, T., Fender, R., Watson, C., & O'Brien, K. (2008). The First Polarimetric Signatures of Infrared Jets in X-Ray Binaries. Astrophysical Journal, 672, https://doi.org/10.1086/523793
• Szeifert, T., Reiss, R., Baksai, P., Deiries, S., Izzo, C., Jehin, E., Kiekebusch, M., Moehler, S., O'Brien, K., Pompei, E., Riquelme, M., Rupprecht, G., & Shen, T.-C. (2007). FORS1 is getting Blue: New Blue Optimised Detectors and High Throughput Filters
• Freudling, W., Møller, P., Patat, F., Moehler, S., Romaniello, M., Jehin, E., O'Brien, K., Izzo, C., Depagne, E., Pompei, E., Naef, D., Rupprecht, G., & Järvinen, A. (2007). Towards Precision Photometry with FORS: A Status Report
• Dhillon, V., Marsh, T., Stevenson, M., Atkinson, D., Kerry, P., Peacocke, P., Vick, A., Beard, S., Ives, D., Lunney, D., McLay, S., Tierney, C., Kelly, J., Littlefair, S., Nicholson, R., Pashley, R., Harlaftis, E., & O'Brien, K. (2007). ULTRACAM: an ultrafast, triple-beam CCD camera for high-speed astrophysics. Monthly Notices of the Royal Astronomical Society, 378, 825-840
• Cornelisse, R., Casares, J., Steeghs, D., Barnes, A., Charles, P., Hynes, R., & O'Brien, K. (2007). A detection of the donor star of Aquila X-1 during its 2004 outburst?. Monthly Notices of the Royal Astronomical Society, 375, 1463-1470
• Dall, T., Foellmi, C., Pritchard, J., Lo Curto, G., Allende Prieto, C., Bruntt, H., Amado, P., Arentoft, T., Baes, M., Depagne, E., Fernandez, M., Ivanov, V., Koesterke, L., Monaco, L., O'Brien, K., Sarro, L., Saviane, I., Scharwächter, J., Schmidtobreick, L., Schütz, O., …Sterzik, M. (2007). VSOP: the variable star one-shot project. I. Project presentation and first data release. Astronomy and Astrophysics, 470, 1201-1214
• Cornelisse, R., Steeghs, D., Casares, J., Charles, P., Barnes, A., Hynes, R., & O'Brien, K. (2007). Optical spectroscopy of the low-mass X-ray binary GX9+9. Monthly Notices of the Royal Astronomical Society, 380, 1219-1229
• Barnes, A., Casares, J., Cornelisse, R., Charles, P., Steeghs, D., Hynes, R., & O'Brien, K. (2007). Kinematical studies of the low-mass X-ray binary GRMus (XB1254-690). Monthly Notices of the Royal Astronomical Society, 380, 1182-1190
• Dhillon, V., Marsh, T., Copperwheat, C., Bezawada, N., Ives, D., Vick, A., & O'Brien, K. (2007). ULTRASPEC: High-speed Spectroscopy with Zero Read-out Noise
• Cornelisse, R., Steeghs, D., Casares, J., Charles, P., Shih, I., Hynes, R., & O'Brien, K. (2007). A signature of the donor star in the extra-galactic X-ray binary LMCX-2. Monthly Notices of the Royal Astronomical Society, 381, 194-200
• Pearson, K., Hynes, R., Steeghs, D., Jonker, P., Haswell, C., King, A., O'Brien, K., Nelemans, G., & Méndez, M. (2006). Multiwavelength Observations of EXO 0748-676. II. Emission-Line Behavior. Astrophysical Journal, 648, 1169-1180
• Hynes, R., Horne, K., O'Brien, K., Haswell, C., Robinson, E., King, A., Charles, P., & Pearson, K. (2006). Multiwavelength Observations of EXO 0748-676. I. Reprocessing of X-Ray Bursts. Astrophysical Journal, 648, 1156-1168
• in't Zand, J., Jonker, P., Nelemans, G., Steeghs, D., & O'Brien, K. (2006). Optical identification of IGR J19140+0951. Astronomy and Astrophysics, 448, 1101-1106
• Casares, J., Cornelisse, R., Steeghs, D., Charles, P., Hynes, R., O'Brien, K., & Strohmayer, T. (2006). Detection of the irradiated donor in the LMXBs 4U 1636-536 (=V801 Ara) and 4U 1735-444 (=V926 Sco). Monthly Notices of the Royal Astronomical Society, 373, 1235-1244
• Kuiper, L., Jonker, P., Hermsen, W., & O'Brien, K. (2005). Chandra imaging of IGR J16493-4348
• Brocksopp, C., Corbel, S., Fender, R., Rupen, M., Sault, R., Tingay, S., Hannikainen, D., & O'Brien, K. (2005). The 2003 radio outburst of a new X-ray transient: XTE J1720-318. Monthly Notices of the Royal Astronomical Society, 356, 125-130
• Vreeswijk, P., Marsh, T., Littlefair, S., Dhillon, V., & O'Brien, K. (2005). GRB 050520: VLT/ULTRACAM observations
• Alloin, D., Mason, E., & O'Brien, K. (2004). The Visit of Prof. R. Sunayev and the Topical Meeting "Accretion onto Compact Objects"
• Hynes, R., Charles, P., van Zyl, L., Barnes, A., Steeghs, D., O'Brien, K., & Casares, J. (2004). Spectroscopy of the optical counterpart to Ser X-1. Monthly Notices of the Royal Astronomical Society, 348, 100-104
• O'Brien, K., Horne, K., Gomer, R. H., Oke, J., & van der Klis, M. (2004). High-speed Keck II and RXTE spectroscopy of Cygnus X-2 - I. Three X-ray components revealed by correlated variability. Monthly Notices of the Royal Astronomical Society, 350, 587-595
• Hynes, R., Steeghs, D., Casares, J., Charles, P., & O'Brien, K. (2004). The Distance and Interstellar Sight Line to GX 339-4. Astrophysical Journal, 609, 317-324
• Hynes, R., Steeghs, D., Casares, J., Charles, P., & O'Brien, K. (2003). Dynamical Evidence for a Black Hole in GX 339-4. Astrophysical Journal, 583, L95-L98
• O'Brien, K., Clarke, F., Fender, R., Brocksopp, C., Steeghs, D., Hynes, R., & Charles, P. (2003). Improved IR (ISAAC/VLT) and radio (ATCA) astrometry of the likely counterpart to XTE J1720-318
• Skidmore, W., O'Brien, K., Horne, K., Gomer, R., Oke, J., & Pearson, K. (2003). High-speed Keck spectroscopy of flares and oscillations in AE Aquarii. Monthly Notices of the Royal Astronomical Society, 338, 1057-1066
• Casares, J., Steeghs, D., Hynes, R., Charles, P., & O'Brien, K. (2003). Bowen Fluorescence from the Companion Star in X1822-371. Astrophysical Journal, 590, 1041-1048
• Hynes, R., Haswell, C., Cui, W., Shrader, C., O'Brien, K., Chaty, S., Skillman, D., Patterson, J., & Horne, K. (2003). The remarkable rapid X-ray, ultraviolet, optical and infrared variability in the black hole XTE J1118+480. Monthly Notices of the Royal Astronomical Society, 345, 292-310
• O'Brien, K., Horne, K., Hynes, R., Chen, W., Haswell, C., & Still, M. (2002). Echoes in X-ray binaries. Monthly Notices of the Royal Astronomical Society, 334, 426-434
• Fender, R., Rayner, D., Trushkin, S., O'Brien, K., Sault, R., Pooley, G., & Norris, R. (2002). Spectral, polarization and time-lag properties of GRS 1915+105 radio oscillations. Monthly Notices of the Royal Astronomical Society, 330, 212-218
• O'Brien, K., Horne, K., Boroson, B., Still, M., Gomer, R., Oke, J., Boyd, P., & Vrtilek, S. (2001). Keck II spectroscopy of mHz quasi-periodic oscillations in Hercules X-1. Monthly Notices of the Royal Astronomical Society, 326, 1067-1075
• Still, M., O'Brien, K., Horne, K., Boroson, B., Titarchuk, L. G., Engle, K., Vrtilek, S. D., Quaintrell, H., & Fiedler, H. (2001). Atmospheric Reflection during an Anomalous Low State of Hercules X-1. Astrophysical Journal, 554, 352-361
• Steeghs, D., O'Brien, K., Horne, K., Gomer, R., & Oke, J. (2001). Emission-line oscillations in the dwarf nova V2051 Ophiuchi. Monthly Notices of the Royal Astronomical Society, 323, 484-496
• Vrtilek, S., Quaintrell, H., Boroson, B., Still, M., Fiedler, H., O'Brien, K., & McCray, R. (2001). Multiwavelength Studies of Hercules X-1 during Short High and Anomalous Low States: On-again, Off-again. Astrophysical Journal, 549, 522-536
• Still, M., O'Brien, K., Horne, K., Hudson, D., Boroson, B., Vrtilek, S. D., Quaintrell, H., & Fiedler, H. (2001). RXTE Observations of Hercules X-1 during the 1998 July Short High State. Astrophysical Journal, 553, 776-787
• Boroson, B., O'Brien, K., Horne, K., Kallman, T., Still, M., Boyd, P. T., Quaintrell, H., & Vrtilek, S. D. (2000). Discovery of Millihertz ULTRAVIOLET Quasi-periodic Oscillations in Hercules X-1. Astrophysical Journal, 545, 399-406
• Hynes, R., Haswell, C., Norton, A., Chaty, S., Solheim, J., Ostensen, R., Abbott, T., Fried, R., McFarland, J., Rolfe, D., Lott, D., Ioannou, Z., Shafter, A., O'Brien, K., Horne, K., Krisciunas, K., & Ivison, R. (1999). XTE J1859+226
• Hynes, R., Haswell, C., Norton, A., Chaty, S., Rolfe, D., Lott, D., Solheim, J.-E., Ostensen, R., Garcia, R., Fried, R., O'Brien, K., Horne, K., Ioannou, Z., Shafter, A., Abbott, T., Krisciunas, K., Ivison, R., Sano, Y., Chen, W., Shrader, C., …Wagner, R. (1999). Optical and near-IR observations of XTE J1859+226
• Hynes, R., O'Brien, K., Horne, K., Chen, W., & Haswell, C. (1998). Echoes from an irradiated disc in GRO J1655-40. Monthly Notices of the Royal Astronomical Society, 299, L37-L41
• Aragon-Salamanca, A., Ellis, R. S., & O'Brien, K. S. (1996). Faint galaxies close to QSOs with damped Lyman alpha absorption systems. Monthly Notices of the Royal Astronomical Society, 281, 945-952

Other (Print)

• Thatte, N. A., Clarke, F., Bryson, I., Shnetler, H., Tecza, M., Fusco, T., Bacon, R. M., Richard, J., Mediavilla, E., Neichel, B., Arribas, S., Garcia-Lorenzo, B., Evans, C. J., Remillieux, A., El Madi, K., Herreros, J. M., Melotte, D., O'Brien, K., Tosh, I. A., Vernet, J., …Larrieu, M. (2016). The E-ELT first light spectrograph HARMONI: capabilities and modes
• Allen, J. R., O'Brien, K., Lynn, J. D., Thatte, N. A., Tosh, I. A., & Tacon, M. (2016). Characterizing the performance of cryogenic lens mounts for the HARMONI spectograph
• Kendrew, S., Zieleniewski, S., Houghton, R. C., Thatte, N., Devriendt, J., Tecza, M., Clarke, F., O'Brien, K., & Häußler, B. (2016). Simulated observations of high-redshift galaxies with the HARMONI spectrograph for the European Extremely Large Telescope
• Güver, T., Mazin, B. A., O'Brien, K., Kay, B., Alis, S., Yelkenci, F. K., Yesilyaprak, C., Yerli, S. K., Erol, A., & Keskin, O. (2016). A microwave kinetic inductance detector for the DAG telescope
• Mazin, B. A., Becker, G., France, K., Fraser, W., Howell, D. A., Jones, T., Meeker, S., O'Brien, K., Prochaska, J. X., Siana, B., Strader, M., Szypryt, P., Tendulkar, S. P., Treu, T., & Vasisht, G. (2015). Science with KRAKENS
• Kalamkar, M., Casella, P., O'Brien, K., Uttley, P., & Maccarone, T. (2015). Fast multi-wavelength broad-band and QPO variability in a black hole X-ray binary: accretion flow and/or a jet origin?
• Plant, D., O'Brien, K., & Fender, R. (2014). Simultaneous independent measurements of a truncated inner accretion disc in the low/hard state of GX 399$-$4
• O'Brien, K., Allen, J. R., Lynn, J. D., Thatte, N. A., Bryson, I., Clarke, F., Schnetler, H., & Tecza, M. (2014). The spectrograph units for the HARMONI integral field spectrograph
• O'Brien, K., Thatte, N., & Mazin, B. (2014). KIDSpec: an MKID based medium resolution integral field spectrograph
• Thatte, N. A., Clarke, F., Bryson, I., Schnetler, H., Tecza, M., Bacon, R. M., Remillieux, A., Mediavilla, E., Herreros Linares, J. M., Arribas, S., Evans, C. J., Lunney, D. W., Fusco, T., O'Brien, K., Tosh, I. A., Ives, D. J., Finger, G., Houghton, R., Davies, R. L., Lynn, J. D., …Neichel, B. (2014). HARMONI: the first light integral field spectrograph for the E-ELT
• Kendrew, S., Zieleniewski, S., Thatte, N., Devriendt, J., Houghton, R., Fusco, T., Tecza, M., Clarke, F., & O'Brien, K. (2014). Integral field spectroscopy of high redshift galaxies with the HARMONI spectrograph on the European Extremely Large Telescope
• Allen, J. R., O'Brien, K., Lynn, J. D., Thatte, N. A., Bryson, I., Clarke, F., Schnetler, H., & Tecza, M. (2014). Cryogenic testing of components for the HARMONI spectrograph
• Clarke, F., Thatte, N., Tecza, M., O'Brien, K., Houghton, R., Tiee, D., Fletcher, L., Irwin, P., Verma, A., Dekany, R., Rick, B., Roberts, J., & Fini, L. (2013). High resolution in three dimensions with SWIFT and PALM3K
• Mazin, B. A., O'Brien, K., Bumble, B., Strader, M., Meeker, S., Stoughton, C., Marsden, D., Walter, A., Szypyrt, P., & Ulbricht, G. (2013). Preliminary Results from the Array Camera for Optical to Near-IR Spectrophotometry (ARCONS)
• Mazin, B. A., Marsden, D., & O'Brien, K. (2012). SuperMOS: a new class of low resolution multiobject spectrographs
• O'Brien, K., Mazin, B., McHugh, S., Meeker, S., Bumble, B., Hanisch, R., & Seaman, R. (2012). ARCONS: a Highly Multiplexed Superconducting UV-to-Near-IR Camera
• Marsden, D., Mazin, B. A., Bumble, B., Meeker, S., O'Brien, K., McHugh, S., Strader, M., & Langman, E. (2012). Optical lumped element microwave kinetic inductance detectors
• O'Brien, K., Mazin, B., McHugh, S., Meeker, S., Marsden, D., & Bumble, B. (2012). ARCONS: a 1024 pixel superconducting integral field spectrograph
• Meeker, S., Mazin, B., O'Brien, K., McHugh, S., Bumble, B., Langman, E., & Navaroli, M. (2012). First Optical Observations with Microwave Kinetic Inductance Detectors
• Casella, P., Maccarone, T. J., & O'Brien, K. (2011). Fast multiwavelength variability from jets in X-ray binaries
• Mazin, B. A., O'Brien, K., McHugh, S., Bumble, B., Moore, D., Golwala, S., & Zmuidzinas, J. (2010). ARCHONS: a highly multiplexed superconducting optical to near-IR camera
• Casella, P., Maccarone, T., O'Brien, K., Fender, R., Russell, D., van der Klis, M., Pe'er, A., Maitra, D., Altamirano, D., Belloni, T., Kanbach, G., Klein-Wolt, M., Mason, E., Migliari, S., Soleri, P., Stefanescu, A., Wiersema, K., & Wijnands, R. (2010). Fast Multiwavelength Variability from Jets in X-ray Binaries, a New Powerful Tool
• Casella, P., Maccarone, T., & O'Brien, K. (2010). Fast multiwavelength variability from jets in X-ray binaries
• Munoz-Darias, T., Martinez-Pais, I., Casares, J., O'Brien, K., Cornelisse, R., Dhillon, V., March, T., Steeghs, D., Charle, P., & Still, M. (2010). Mapping LMXBs with reprocessed X-ray bursts
• Britt, C. T., Hynes, R., Mikles, V., Robinson, E., & O'Brien, K. (2010). Echo-mapping of Scorpius X-1
• Cornelisse, R., Casares, J., Steeghs, D., Charles, P., Barnes, A., Hynes, R., O'Brien, K., & Muñoz-Darias, T. (2010). The Bowen Survey; detecting donor star signatures in low mass X-ray binaries
• Shahbaz, T., Fender, R., Watson, C., & O'Brien, K. (2009). Polarimetric signatures of infrared jets in X-ray binaries
• Nelemans, G., Wood, M., Groot, P., Anderson, S., Belczynski, K., Benacquista, M., Charles, P., Cumming, A., Deloye, C., Jonker, P., Kalogera, V., Knigge, C., Marsh, T., Motl, P., Napiwotzki, R., O'Brien, K., Phinney, E., Ramsay, G., Shahbaz, T., Solheim, J.-E., …Yungelson, L. (2009). The astrophysics of ultra-compact binaries
• Foellmi, C., Dall, T., Pritchard, J., Allende Prieto, C., Bruntt, H., Amado, P., Arentoft, T., Baes, M., Depagne, E., Fernandez, M., Ivanov, V., Koesterke, L., Monaco, L., O'Brien, K., Sarro, L., Saviane, I., Scharwaechter, J., Schmidtobreick, L., Schütz, O., Seifahrt, A., …Osuna, P. (2008). The Variable Star One-shot Project, and its little child: Wikimbad
• Walsh, J., Kuntschner, H., Jehin, E., Kaufer, A., O'Brien, K., Riquelme, M., Smette, A., & Kerber, F. (2008). Modelling the Fringing of the FORS2 CCD
• Shahbaz, T., Fender, R., Watson, C., O'Brien, K., Wachter, S., Gelino, D., & Gelino, C. R. (2008). Polarimetric Signatures of Infrared Jets in X-ray Binaries
• Freudling, W., Møller, P., Patat, F., Moehler, S., Romaniello, M., Jehin, E., O'Brien, K., Izzo, C., Pompei, E., & Kerber, F. (2008). Photometry with FORS
• O'Brien, K., Leahy, D. A., & Hobill, D. W. (2008). Fast Spectroscopy and Imaging with the FORS2 HIT Mode
• Muñoz-Darias, T., Martínee-Pails, I., Casares, J., Cornelisse, R., Dhillon, V., Marsh, T., Steeghs, D., O'Brien, K., Charles, P., Still, M., Wachter, S., Gelino, D., & Gelino, C. R. (2008). Bowen Blend Echo-Tomography of Sco X-l and V801 Ara
• Cornelisse, R., Casares, J., Muñoz-Darias, T., Steeghs, D., Charles, P., Hynes, R., O'Brien, K., Barnes, A., Wachter, S., Gelino, D., & Gelino, C. R. (2008). An Overview of the Bowen Survey: Detecting Donor Star Signatures in Low Mass X-ray Binaries
• Muñoz-Darias, T., Martinez-Pais, I. G., Casares, J., Dhillon, V., Marsh, T., Steeghs, D., O'Brien, K., Charles, P., Still, M., & Cornelisse, R. (2008). Bowen Blend Echo-tomography of Neutron Star LMXBs
• Hynes, R. I., Robinson, E. L., Bayless, A., O'Brien, K., Wachter, S., Gelino, D., & Gelino, C. R. (2008). Echo Tomography of Cygnus X-2
• Muñoz-Darias, T., Martínez-Pais, I., Casares, J., Cornelisse, R., Dhillon, V., Marsh, T., Steeghs, D., O'Brien, K., Charles, P., Still, M., Ryan, O., & Shearer, A. (2008). Bowen blend echo-tomography of low mass X-ray binaries
• Dhillon, V., Marsh, T., Copperwheat, C., Bezawada, N., Ives, D., Vick, A., O'Brien, K., Ryan, O., & Shearer, A. (2008). ULTRASPEC: High-speed spectroscopy with zero readout noise
• Schmidtobreick, L., Bagnulo, S., Jehin, E., Marconi, G., O'Brien, K., Pompei, E., Saviane, I., & Kerber, F. (2008). IOT Overview: Optical Multi-Object Spectrographs
• Mason, E., Israel, G. L., O'Brien, K., Ryan, O., & Shearer, A. (2008). FORS2 HIT Mode: Phase Resolved Spectroscopy of RXJ0806.3+1527
• Freudling, W., Romaniello, M., Patat, F., Møller, P., Jehin, E., & O'Brien, K. (2007). Photometry with FORS at the ESO VLT
• Skidmore, W., Horne, K., Pearson, K., Gomer, R., O'Brien, K., Oke, B., & Sion, E. (2004). Rapid Keck Spectroscopy of Cataclysmic Variables
• Skidmore, W., Gomer, R., Horne, K., O'Brien, K., Oke, B., Pearson, K., & Cropper, M. (2004). High Speed Keck Spectroscopy of Flickering in AM Her
• Casares, J., Steeghs, D., Hynes, R., Charles, P., Cornelisse, R., O'Brien, K., & Sion, E. (2004). Bowen Fluorescence from Companion Stars in X-ray Binaries
• Hynes, R., Haswell, C., Robinson, E., Horne, K., O'Brien, K., Charles, P., King, A., Rolfe, D., & Sion, E. (2004). Disentangling X-ray Reprocessing Sites in EXO 0748-676
• Hynes, R., Haswell, C., Chaty, S., Cui, W., Shrader, C., O'Brien, K., Horne, K., Fuchs, Y., & Rodriguez, J. (2003). X-ray/UV correlations in XTE J1118+480: disc, jet, or something else?
• Hynes, R., Steeghs, D., Casares, J., Charles, P., & O'Brien, K. (2003). Dynamical Evidence for a Black Hole in GX339-4
• Skidmore, W., Pearson, K., O'Brien, K., Horne, K., Gomer, R., Beuermann, K., & Reinsch, K. (2002). Fireballs and oscillations in AE Aqr
• O'Brien, K. (2001). Rapid optical spectroscopy of X-ray binaries with Keck II
• O'Brien, K., Horne, K., Steeghs, D., & Cuypers, J. (2001). Echoes in X-ray Binaries: Mapping the Accretion Flow
• Still, M., O'Brien, K., Horne, K., Boroson, B., Vrtilek, S., Titarchuk, L., Quaintrell, H., & Fiedler, H. (2000). Atmospheric reflection during the anomalous low-state of Hercules X-1
• O'Brien, K., & Horne, K. (2000). Correlated X-ray and optical variability in X-ray Binaries
• Vrtilek, S., Boroson, B., Still, M., Fiedler, H., Quaintrell, H., & O'Brien, K. (1999). Yet Another Multi wavelength Campaign on Hercules X-1/HZ Herculis
• Hynes, R., Haswell, C., Fender, R., Shrader, C., Chen, W., Horne, K., Harlaftis, E., O'Brien, K., Hellier, C., Kemp, J., Kuulkers, E., & Woodward, C. (1998). The 1996 Outburst of GRO J1655-40
• Still, M., O'Brien, K., & Horne, K. (1998). An Observatory for Mapping Stellar Accretion Discs
• Hynes, R., Haswell, C., Shrader, C., Chen, W., Horne, K., Harlaftis, E., O'Brien, K., Hellier, C., Fender, R., Kuulkers, E., & Woodward, C. (1998). The 1996 Outburst of GRO J1655-40: The Challenge of Interpreting the Multiwavelength Spectra
• Still, M., O'Brien, K., & Horne, K. (1998). Echo-sounding the accretion disks of X-ray binaries