F. Riddick - Academia.edu (original) (raw)

Papers by F. Riddick

Research paper thumbnail of Supernova 2014J at M82 – II. Direct analysis of a middle-class Type Ia supernova

Monthly Notices of the Royal Astronomical Society, 2016

Research paper thumbnail of GRB 110520A: WHT IR observations

Research paper thumbnail of A test implementation of the core manufacturing simulation data specification

2007 Winter Simulation Conference, 2007

This paper describes an effort of testing the Core Manufacturing Simulation Data (CMSD) informati... more This paper describes an effort of testing the Core Manufacturing Simulation Data (CMSD) information model as a neutral data interface for a discrete event simulation model developed using Enterprise Dynamics. The implementation is based upon a model of a paint shop at a Volvo Car Corporation plant in Sweden. The model is built for a Swedish research project (FACTS), which focuses on the work procedure of developing new and modified production systems. FACTS has found standardized simulation data structures to be of high interest to achieve efficient data collection in conceptual stages of production development programs. For the CMSD-development team, implementations serve as an approach to validate the structures in CMSD and to gather requirements for future enhancements. CMSD was originally developed to support job shops, but the results of this implementation indicate a good possibility to extend CMSD to also support flow shops.

Research paper thumbnail of Infrared spectroscopy and analysis of brown dwarf and planetary mass objects in the Orion nebula cluster

Monthly Notices of the Royal Astronomical Society, 2009

We present near-infrared long slit and multi-slit spectra of low mass brown dwarf candidates in t... more We present near-infrared long slit and multi-slit spectra of low mass brown dwarf candidates in the Orion Nebula Cluster. The long slit data were observed in the H-& K-bands using NIRI on the Gemini North Telescope. The multi-object spectroscopic observations were made using IRIS2 on the Anglo Australian Telescope at H-band. We develop a spectral typing scheme based on optically calibrated, near infrared spectra of young sources in the Taurus and IC 348 star forming regions with spectral types M3.0 to M9.5. We apply our spectral typing scheme to 52 sources, including previously published UKIRT and GNIRS spectra. 40 objects show strong water absorption with spectral types of M3 to >M9.5. The latest type objects are provisionally classified as early L types. We plot our sources on H-R diagrams overlaid with theoretical premain-sequence isochrones. The majority of our objects lie close to or above the 1 Myr isochrone, leading to an average cluster age that is <1 Myr. We find 38 sources lie at or below the hydrogen burning limit (0.075 M ⊙ ). 10 sources potentially have masses below the deuterium burning limit (0.012 M ⊙ ). We use a Monte Carlo approach to model the observed luminosity function with a variety of cluster age and mass distributions. The lowest χ 2 values are produced by an age distribution centred at 1 Myr, with a mass function that declines at sub-stellar masses according to an M α power law in the range α=0.3 to 0.6. We find that truncating the mass function at 0.012 M ⊙ produces luminosity functions that are starved of the faintest magnitudes, even when using bimodal age populations that contain 10 Myr old sources. The results of these Monte Carlo simulations therefore support the existence of a planetary mass population in the ONC.

Research paper thumbnail of Erratum: Infrared spectroscopy and analysis of brown dwarf and planetary mass objects in the Orion nebula cluster

Monthly Notices of the Royal Astronomical Society, 2009

Research paper thumbnail of GRB 110520A: WHT IR observations

Research paper thumbnail of First EURONEAR NEA discoveries from La Palma using the INT

Monthly Notices of the Royal Astronomical Society, 2015

Since 2006, the European Near Earth Asteroids Research (EURONEAR) project has been contributing t... more Since 2006, the European Near Earth Asteroids Research (EURONEAR) project has been contributing to the research of near-Earth asteroids (NEAs) within a European network. One of the main aims is the amelioration of the orbits of NEAs, and starting in 2014 February we focus on the recovery of one-opposition NEAs using the Isaac Newton Telescope (INT) in La Palma in override mode. Part of this NEA recovery project, since 2014 June EURONEAR serendipitously started to discover and secure the first NEAs from La Palma and using the INT, thanks to the teamwork including amateurs and students who promptly reduce the data, report discoveries and secure new objects recovered with the INT and few other telescopes from the EURONEAR network. Five NEAs were discovered with the INT, including 2014 LU14, 2014 NL52 (one very fast rotator), 2014 OL339 (the fourth known Earth quasi-satellite), 2014 SG143 (a quite large NEA), and 2014 VP. Another very fast moving NEA was discovered but was unfortunately lost due to lack of follow-up time. Additionally, another 14 NEA candidates were identified based on two models, all being rapidly followed-up using the INT and another 11 telescopes within the EURONEAR network. They include one object discovered by Pan-STARRS, two Mars crossers, two Hungarias, one Jupiter trojan, and other few inner main belt asteroids (MBAs). Using the INT and Sierra Nevada 1.5 m for photometry, then the Gran Telescopio de Canarias for spectroscopy, we derived the very rapid rotation of 2014 NL52, then its albedo, magnitude, size, and its spectral class. Based on the total sky coverage in dark conditions, we evaluate the actual survey discovery rate using 2-m class telescopes. One NEA is possible to be discovered randomly within minimum 2.8 deg 2 and maximum 5.5 deg 2 . These findings update our past statistics, being based on double sky coverage and taking into account the recent increase in discovery.

Research paper thumbnail of Supernova 2014J at M82 – II. Direct analysis of a middle-class Type Ia supernova

Monthly Notices of the Royal Astronomical Society, 2016

Research paper thumbnail of GRB 110520A: WHT IR observations

Research paper thumbnail of A test implementation of the core manufacturing simulation data specification

2007 Winter Simulation Conference, 2007

This paper describes an effort of testing the Core Manufacturing Simulation Data (CMSD) informati... more This paper describes an effort of testing the Core Manufacturing Simulation Data (CMSD) information model as a neutral data interface for a discrete event simulation model developed using Enterprise Dynamics. The implementation is based upon a model of a paint shop at a Volvo Car Corporation plant in Sweden. The model is built for a Swedish research project (FACTS), which focuses on the work procedure of developing new and modified production systems. FACTS has found standardized simulation data structures to be of high interest to achieve efficient data collection in conceptual stages of production development programs. For the CMSD-development team, implementations serve as an approach to validate the structures in CMSD and to gather requirements for future enhancements. CMSD was originally developed to support job shops, but the results of this implementation indicate a good possibility to extend CMSD to also support flow shops.

Research paper thumbnail of Infrared spectroscopy and analysis of brown dwarf and planetary mass objects in the Orion nebula cluster

Monthly Notices of the Royal Astronomical Society, 2009

We present near-infrared long slit and multi-slit spectra of low mass brown dwarf candidates in t... more We present near-infrared long slit and multi-slit spectra of low mass brown dwarf candidates in the Orion Nebula Cluster. The long slit data were observed in the H-& K-bands using NIRI on the Gemini North Telescope. The multi-object spectroscopic observations were made using IRIS2 on the Anglo Australian Telescope at H-band. We develop a spectral typing scheme based on optically calibrated, near infrared spectra of young sources in the Taurus and IC 348 star forming regions with spectral types M3.0 to M9.5. We apply our spectral typing scheme to 52 sources, including previously published UKIRT and GNIRS spectra. 40 objects show strong water absorption with spectral types of M3 to >M9.5. The latest type objects are provisionally classified as early L types. We plot our sources on H-R diagrams overlaid with theoretical premain-sequence isochrones. The majority of our objects lie close to or above the 1 Myr isochrone, leading to an average cluster age that is <1 Myr. We find 38 sources lie at or below the hydrogen burning limit (0.075 M ⊙ ). 10 sources potentially have masses below the deuterium burning limit (0.012 M ⊙ ). We use a Monte Carlo approach to model the observed luminosity function with a variety of cluster age and mass distributions. The lowest χ 2 values are produced by an age distribution centred at 1 Myr, with a mass function that declines at sub-stellar masses according to an M α power law in the range α=0.3 to 0.6. We find that truncating the mass function at 0.012 M ⊙ produces luminosity functions that are starved of the faintest magnitudes, even when using bimodal age populations that contain 10 Myr old sources. The results of these Monte Carlo simulations therefore support the existence of a planetary mass population in the ONC.

Research paper thumbnail of Erratum: Infrared spectroscopy and analysis of brown dwarf and planetary mass objects in the Orion nebula cluster

Monthly Notices of the Royal Astronomical Society, 2009

Research paper thumbnail of GRB 110520A: WHT IR observations

Research paper thumbnail of First EURONEAR NEA discoveries from La Palma using the INT

Monthly Notices of the Royal Astronomical Society, 2015

Since 2006, the European Near Earth Asteroids Research (EURONEAR) project has been contributing t... more Since 2006, the European Near Earth Asteroids Research (EURONEAR) project has been contributing to the research of near-Earth asteroids (NEAs) within a European network. One of the main aims is the amelioration of the orbits of NEAs, and starting in 2014 February we focus on the recovery of one-opposition NEAs using the Isaac Newton Telescope (INT) in La Palma in override mode. Part of this NEA recovery project, since 2014 June EURONEAR serendipitously started to discover and secure the first NEAs from La Palma and using the INT, thanks to the teamwork including amateurs and students who promptly reduce the data, report discoveries and secure new objects recovered with the INT and few other telescopes from the EURONEAR network. Five NEAs were discovered with the INT, including 2014 LU14, 2014 NL52 (one very fast rotator), 2014 OL339 (the fourth known Earth quasi-satellite), 2014 SG143 (a quite large NEA), and 2014 VP. Another very fast moving NEA was discovered but was unfortunately lost due to lack of follow-up time. Additionally, another 14 NEA candidates were identified based on two models, all being rapidly followed-up using the INT and another 11 telescopes within the EURONEAR network. They include one object discovered by Pan-STARRS, two Mars crossers, two Hungarias, one Jupiter trojan, and other few inner main belt asteroids (MBAs). Using the INT and Sierra Nevada 1.5 m for photometry, then the Gran Telescopio de Canarias for spectroscopy, we derived the very rapid rotation of 2014 NL52, then its albedo, magnitude, size, and its spectral class. Based on the total sky coverage in dark conditions, we evaluate the actual survey discovery rate using 2-m class telescopes. One NEA is possible to be discovered randomly within minimum 2.8 deg 2 and maximum 5.5 deg 2 . These findings update our past statistics, being based on double sky coverage and taking into account the recent increase in discovery.