Noah Brosch | Tel Aviv University (original) (raw)

Books by Noah Brosch

This book will appeal to all researchers that have an interest in the current Leonid showers. It ... more This book will appeal to all researchers that have an interest in the current Leonid showers. It contains over forty research papers that present some of the first observational results of the November 1999 Leonid meteor storm, the first storm observed by modern observing techniques. The book is a first glimpse of the large amount of information obtained during NASA's Leonid Multi-Instrument Aircraft Campaign and groundbased campaigns throughout the world. It provides an excellent overview on the state of meteor shower research for any professional researcher or amateur meteor observer interested in studies of meteors and meteoroids and their relation to comets, the origin of life on Earth, the satellite impact hazard issue, and upper atmosphere studies of neutral atom chemistry, the formation of meteoric debris, persistent trains, airglow, noctilucent clouds, sprites and elves.

Since very early times Sirius was a point of attraction in the night sky. It served to synchroniz... more Since very early times Sirius was a point of attraction in the night sky. It served to synchronize calendars in antiquity and was the subject of many myths and legends, including some modern ones. It was perceived as a red star for more than 400 years, but such reports were relegated to the Mediterranean region. Astronomically, Sirius is a very bright star. This, and its present close distance to us, argues in favor of it being the target of detailed studies of stellar structure and evolution. Its binary nature, with a companion that is one of the more massive white dwarfs, is an additional reason for such studies. This book collects the published information on Sirius in an attempt to
derive a coherent picture of how this system came to look as it does....

Papers by Noah Brosch

Icarus, 2011

The evolution of the spin rate of Comet 9P/Tempel 1 through two perihelion passages (in 2000 and ... more The evolution of the spin rate of Comet 9P/Tempel 1 through two perihelion passages (in 2000 and 2005) is determined from 1922 Earth-based observations taken over a period of 13 year as part of a World-Wide observing campaign and from 2888 observations taken over a period of 50 days from the Deep Impact spacecraft. We determine the following sidereal spin rates (periods): 209.023 ± 0.025°/dy (41.335 ± 0.005 h) prior to the 2000 perihelion passage, 210.448 ± 0.016°/dy (41.055 ± 0.003 h) for the interval between the 2000 and 2005 perihelion passages, 211.856 ± 0.030°/dy (40.783 ± 0.006 h) from Deep Impact photometry just prior to the 2005 perihelion passage, and 211.625 ± 0.012°/dy (40.827 ± 0.002 h) in the interval 2006-2010 following the 2005 perihelion passage. The period decreased by 16.8 ± 0.3 min during the 2000 passage and by 13.7 ± 0.2 min during the 2005 passage suggesting a secular decrease in the net torque. The change in spin rate is asymmetric with respect to perihelion with the maximum net torque being applied on approach to perihelion. The Deep Impact data alone show that the spin rate was increasing at a rate of 0.024 ± 0.003°/dy/dy at JD2453530.60510 (i.e., 25.134 dy before impact), which provides independent confirmation of the change seen in the Earth-based observations.

Interferometry for Optical Astronomy II, 2003

We propose to modify the solar collector PETAL (Photon Energy Transformation & Astrophysics Labor... more We propose to modify the solar collector PETAL (Photon Energy Transformation & Astrophysics Laboratory) for astronomy. The mirror is a segmented parabolic dish collector, which has a relatively poor imaging quality. The conversion can be done by either of two principal methods: (1) phasing the surface of the collector itself or significant sections thereof; (2) transforming the structure into an optical interferometer by mounting small telescopes around its rim, and using fibre optics to combine the light at a common focus.

Planetary and Space Science, 2015

We present the results of a global coma morphology campaign for comet C/2012 S1 (ISON), which was... more We present the results of a global coma morphology campaign for comet C/2012 S1 (ISON), which was organized to involve both professional and amateur observers. In response to the campaign, many hundreds of images, from nearly two dozen groups were collected. Images were taken primarily in the continuum, which help to characterize the behavior of dust in the coma of comet ISON. The campaign received images from January 12 through November 22, 2013 (an interval over which the heliocentric distance decreased from 5.1 AU to 0.35 AU), allowing monitoring of the long-term evolution of coma morphology during comet ISON's pre-perihelion leg. Data were contributed by observers spread around the world, resulting in particularly good temporal coverage during November when comet ISON was brightest but its visibility was limited from any one location due to the small solar elongation. We analyze the northwestern sunward continuum coma feature observed in comet ISON during the first half of 2013, finding that it was likely present from at least February through May and did not show variations on diurnal time scales. From these images we constrain the grain velocities to ~10 m s-1, and we find that the grains spent 2-4 weeks in the sunward side prior to merging with the dust tail. We present a rationale for the lack of continuum coma features from September until mid-November 2013, determining that if the feature from the first half of 2013 was present, it was likely too small to be clearly detected. We also analyze the continuum coma morphology observed subsequent to the November 12 outburst, and constrain the first appearance of new features in the continuum to later than November 13.99 UT.

Astronomy and …, 1993

... Germany M. Hoffmann, EH Geyer Pic do Midi Obs., France J. Lecacheux, B. Sicardy, C. Buil, F. ... more ... Germany M. Hoffmann, EH Geyer Pic do Midi Obs., France J. Lecacheux, B. Sicardy, C. Buil, F. Colas, A. Klotz, F. Thouvenot, JL Vidal Vatican Ohs., Italy E. Carreira, F. Rossi Catania Obs., Italy C. Blanco, S. Cristaldi Em Harod, Israel HJ Reitsema, Y. Nevo Wise Ohs. ...

With every new discovery of an extra-solar planet, the absence of planets in globular clusters (G... more With every new discovery of an extra-solar planet, the absence of planets in globular clusters (GCs) becomes
more and more conspicuous. Null detection of transiting hot Jupiters in globular clusters 47 Tuc,
omega Cen and NGC6397 presents an important puzzle, raising questions about the role played by cluster
metallicity and environment on formation and survival of planetary systems in densely populated stellar clusters.
GCs were postulated to have many free-floating planets, for which the microlensing (ML) is an established
tool for detection. Dense environment, well-constrained distances and kinematics of lenses and sources, and
photometry of thousands of stars simultaneously make GCs the ideal targets to search for the microlensing.
We present first results of a multi-site, 69-nights long campaign to search for ML signatures of
low-mass objects in the globular cluster M4, which was chosen due to its proximity, location and an actual existence
of a planet. M4 was observed in R and I bands by two telescopes, 1-m T40 and 18-inch C18, of WISE Observatory,
Tel Aviv, Israel, from April to July 2011. Observations on 1-m telescope were carried out in service mode, gathering
6 to 18 20-sec exposures a night for a total of 69 nights. C18 observations were done for about 4 hrs a night for 7
nights in May 2011. We employ the semi-automated pipeline to calibrate and reduce the images to the light curves
that our group is developing for this purpose which includes the differential photometry package DIAPL,
written by Wozniak and modified by W. Pych. Several different diagnostics are employed for search of variability/transients.
While no high-significance ML event was found in this observational run, we have detected more than twenty new variables
and variable candidates in M4 field, which we present here.

Future EUV/UV and Visible Space Astrophysics Missions and Instrumentation, 2003

The World Space Observatory is an unconventional space project proceeding via distributed studies... more The World Space Observatory is an unconventional space project proceeding via distributed studies. The present design, verified for feasibilty, consists of a 1.7-meter telescope operating at the second Largangian point of the Earth-Sun system. The focal plane instruments consist of three UV spectrometers covering the spectral band from Lyman alpha to the atmospheric cutoff with R~55,000 and offering long-slit capability over the same band with R~1,000. In addition, a number of UV and optical imagers view adjacent fields to that sampled by the spectrometers. Their performance compares well with that of HST/ACS and the spectral capabilities of WSO rival those of HST/COS. The WSO, as presently conceived, will be constructed and operated with the same distributed philosophy. This will allow as many groups and countries to participate, each contributing as much as feasible but allowing multi-national participation. Although designed originally with a conservative approach, the WSO embodies some innovative ideas and will allow a world-class mission to be realized with a moderate budget.

Astrophysics and Space Science, 2014

ABSTRACT Space astronomy in the last 40 years has largely been done from spacecraft in low Earth ... more ABSTRACT Space astronomy in the last 40 years has largely been done from spacecraft in low Earth orbit (LEO) for which the technology is proven and delivery mechanisms are readily available. However, new opportunities are arising with the surge in commercial aerospace missions. We describe here one such possibility: deploying a small instrument on the Moon. This can be accomplished by flying onboard the Indian entry to the Google Lunar X PRIZE competition, Team Indus mission, which is expected to deliver a nearly 30 kgs of payloads to the Moon, with a rover as its primary payload. We propose to mount a wide-field far-UV (130–180 nm) imaging telescope as a payload on the Team Indus lander. Our baseline operation is a fixed zenith pointing but with the option of a mechanism to allow observations of different attitudes. Pointing towards intermediate ecliptic latitude (50∘ or above) ensures that the Sun is at least 40∘ off the line of sight at all times. In this position, the telescope can cover higher galactic latitudes as well as parts of Galactic plane. The scientific objectives of such a prospective are delineated and discussed.

Despite the spectrographic evidence for wind-driven mass loss from erupting dwarf novae, almost n... more Despite the spectrographic evidence for wind-driven mass loss from erupting dwarf novae, almost no visible shells surrounding these systems have ever been detected. Theory predicts that the white dwarfs in all dwarf novae must eventually accrete enough mass to undergo classical nova eruptions, but not a single dwarf nova has ever been shown to have undergone a classical nova eruption.

We present the fifth list with results of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS ... more We present the fifth list with results of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS therein, SAO - Special Astrophysical Observatory, Russia). The list is a result of follow-up spectroscopy conducted with the 2.2m CAHA and 4m Kitt Peak telescopes in 1999. The data of this snap-shot spectroscopy survey confirmed 166 emission-line objects out of 209 observed candidates and allowed

An international facility to store, catalogue and digitise photographic plates is under developme... more An international facility to store, catalogue and digitise photographic plates is under development at the Royal Observatory of Belgium in Uccle-Brussels. The creation of such a facility requires a well-organized effort and substantial resources. However, the cost is not exorbitantly high if one takes advantage of the new generation of commercial, photogrammetric, flatbed scanners, which use the latest CCD technology.

ESO ASTROPHYSICS SYMPOSIA, 2004

The World Space Observatory (WSO/UV) is a space project for an ultraviolet telescope which has to... more The World Space Observatory (WSO/UV) is a space project for an ultraviolet telescope which has to fulfill the needs and scientific requirements of a worldwide community. For this very reason, the project development is distributed among many countries, scientific institutes and companies. The technical requirements relevant for the AVO efficient performance have to be included and improved for the WSO/UV

Early-type dwarf galaxies dominate cluster populations, but their formation and evolutionary hist... more Early-type dwarf galaxies dominate cluster populations, but their formation and evolutionary histories are poorly understood. The ALFALFA (Arecibo Legacy Fast ALFA) blind survey is providing a census of HI in galaxies of all types in a range of environments. Here we report ALFALFA and follow-up H-alpha imaging results for Virgo Cluster early-type dwarfs at declinations between 4 and 16 degrees.

The Leo region offers a detailed view of several nearby groups of galaxies including Leo I at 10.... more The Leo region offers a detailed view of several nearby groups of galaxies including Leo I at 10.4 Mpc and another slightly more distant structure within the Local Supercluster (Leo II). Leo I is of particular interest because it contains both a large ring of intergalactic gas of unknown origin (the Leo Ring) as well as a long tidal stream

One of the principal drivers of the ALFALFA survey is the exploration of the dynamics of the Virg... more One of the principal drivers of the ALFALFA survey is the exploration of the dynamics of the Virgo cluster and its environs via the cataloguing of all of its gas-rich members and tracing disruptive events through the HI remnants they leave behind. The wide area coverage provided by ALFALFA is ideal for the study of extended source structures, and its

This book will appeal to all researchers that have an interest in the current Leonid showers. It ... more This book will appeal to all researchers that have an interest in the current Leonid showers. It contains over forty research papers that present some of the first observational results of the November 1999 Leonid meteor storm, the first storm observed by modern observing techniques. The book is a first glimpse of the large amount of information obtained during NASA's Leonid Multi-Instrument Aircraft Campaign and groundbased campaigns throughout the world. It provides an excellent overview on the state of meteor shower research for any professional researcher or amateur meteor observer interested in studies of meteors and meteoroids and their relation to comets, the origin of life on Earth, the satellite impact hazard issue, and upper atmosphere studies of neutral atom chemistry, the formation of meteoric debris, persistent trains, airglow, noctilucent clouds, sprites and elves.

Since very early times Sirius was a point of attraction in the night sky. It served to synchroniz... more Since very early times Sirius was a point of attraction in the night sky. It served to synchronize calendars in antiquity and was the subject of many myths and legends, including some modern ones. It was perceived as a red star for more than 400 years, but such reports were relegated to the Mediterranean region. Astronomically, Sirius is a very bright star. This, and its present close distance to us, argues in favor of it being the target of detailed studies of stellar structure and evolution. Its binary nature, with a companion that is one of the more massive white dwarfs, is an additional reason for such studies. This book collects the published information on Sirius in an attempt to
derive a coherent picture of how this system came to look as it does....

Icarus, 2011

The evolution of the spin rate of Comet 9P/Tempel 1 through two perihelion passages (in 2000 and ... more The evolution of the spin rate of Comet 9P/Tempel 1 through two perihelion passages (in 2000 and 2005) is determined from 1922 Earth-based observations taken over a period of 13 year as part of a World-Wide observing campaign and from 2888 observations taken over a period of 50 days from the Deep Impact spacecraft. We determine the following sidereal spin rates (periods): 209.023 ± 0.025°/dy (41.335 ± 0.005 h) prior to the 2000 perihelion passage, 210.448 ± 0.016°/dy (41.055 ± 0.003 h) for the interval between the 2000 and 2005 perihelion passages, 211.856 ± 0.030°/dy (40.783 ± 0.006 h) from Deep Impact photometry just prior to the 2005 perihelion passage, and 211.625 ± 0.012°/dy (40.827 ± 0.002 h) in the interval 2006-2010 following the 2005 perihelion passage. The period decreased by 16.8 ± 0.3 min during the 2000 passage and by 13.7 ± 0.2 min during the 2005 passage suggesting a secular decrease in the net torque. The change in spin rate is asymmetric with respect to perihelion with the maximum net torque being applied on approach to perihelion. The Deep Impact data alone show that the spin rate was increasing at a rate of 0.024 ± 0.003°/dy/dy at JD2453530.60510 (i.e., 25.134 dy before impact), which provides independent confirmation of the change seen in the Earth-based observations.

Interferometry for Optical Astronomy II, 2003

We propose to modify the solar collector PETAL (Photon Energy Transformation & Astrophysics Labor... more We propose to modify the solar collector PETAL (Photon Energy Transformation & Astrophysics Laboratory) for astronomy. The mirror is a segmented parabolic dish collector, which has a relatively poor imaging quality. The conversion can be done by either of two principal methods: (1) phasing the surface of the collector itself or significant sections thereof; (2) transforming the structure into an optical interferometer by mounting small telescopes around its rim, and using fibre optics to combine the light at a common focus.

Planetary and Space Science, 2015

We present the results of a global coma morphology campaign for comet C/2012 S1 (ISON), which was... more We present the results of a global coma morphology campaign for comet C/2012 S1 (ISON), which was organized to involve both professional and amateur observers. In response to the campaign, many hundreds of images, from nearly two dozen groups were collected. Images were taken primarily in the continuum, which help to characterize the behavior of dust in the coma of comet ISON. The campaign received images from January 12 through November 22, 2013 (an interval over which the heliocentric distance decreased from 5.1 AU to 0.35 AU), allowing monitoring of the long-term evolution of coma morphology during comet ISON's pre-perihelion leg. Data were contributed by observers spread around the world, resulting in particularly good temporal coverage during November when comet ISON was brightest but its visibility was limited from any one location due to the small solar elongation. We analyze the northwestern sunward continuum coma feature observed in comet ISON during the first half of 2013, finding that it was likely present from at least February through May and did not show variations on diurnal time scales. From these images we constrain the grain velocities to ~10 m s-1, and we find that the grains spent 2-4 weeks in the sunward side prior to merging with the dust tail. We present a rationale for the lack of continuum coma features from September until mid-November 2013, determining that if the feature from the first half of 2013 was present, it was likely too small to be clearly detected. We also analyze the continuum coma morphology observed subsequent to the November 12 outburst, and constrain the first appearance of new features in the continuum to later than November 13.99 UT.

Astronomy and …, 1993

... Germany M. Hoffmann, EH Geyer Pic do Midi Obs., France J. Lecacheux, B. Sicardy, C. Buil, F. ... more ... Germany M. Hoffmann, EH Geyer Pic do Midi Obs., France J. Lecacheux, B. Sicardy, C. Buil, F. Colas, A. Klotz, F. Thouvenot, JL Vidal Vatican Ohs., Italy E. Carreira, F. Rossi Catania Obs., Italy C. Blanco, S. Cristaldi Em Harod, Israel HJ Reitsema, Y. Nevo Wise Ohs. ...

With every new discovery of an extra-solar planet, the absence of planets in globular clusters (G... more With every new discovery of an extra-solar planet, the absence of planets in globular clusters (GCs) becomes
more and more conspicuous. Null detection of transiting hot Jupiters in globular clusters 47 Tuc,
omega Cen and NGC6397 presents an important puzzle, raising questions about the role played by cluster
metallicity and environment on formation and survival of planetary systems in densely populated stellar clusters.
GCs were postulated to have many free-floating planets, for which the microlensing (ML) is an established
tool for detection. Dense environment, well-constrained distances and kinematics of lenses and sources, and
photometry of thousands of stars simultaneously make GCs the ideal targets to search for the microlensing.
We present first results of a multi-site, 69-nights long campaign to search for ML signatures of
low-mass objects in the globular cluster M4, which was chosen due to its proximity, location and an actual existence
of a planet. M4 was observed in R and I bands by two telescopes, 1-m T40 and 18-inch C18, of WISE Observatory,
Tel Aviv, Israel, from April to July 2011. Observations on 1-m telescope were carried out in service mode, gathering
6 to 18 20-sec exposures a night for a total of 69 nights. C18 observations were done for about 4 hrs a night for 7
nights in May 2011. We employ the semi-automated pipeline to calibrate and reduce the images to the light curves
that our group is developing for this purpose which includes the differential photometry package DIAPL,
written by Wozniak and modified by W. Pych. Several different diagnostics are employed for search of variability/transients.
While no high-significance ML event was found in this observational run, we have detected more than twenty new variables
and variable candidates in M4 field, which we present here.

Future EUV/UV and Visible Space Astrophysics Missions and Instrumentation, 2003

The World Space Observatory is an unconventional space project proceeding via distributed studies... more The World Space Observatory is an unconventional space project proceeding via distributed studies. The present design, verified for feasibilty, consists of a 1.7-meter telescope operating at the second Largangian point of the Earth-Sun system. The focal plane instruments consist of three UV spectrometers covering the spectral band from Lyman alpha to the atmospheric cutoff with R~55,000 and offering long-slit capability over the same band with R~1,000. In addition, a number of UV and optical imagers view adjacent fields to that sampled by the spectrometers. Their performance compares well with that of HST/ACS and the spectral capabilities of WSO rival those of HST/COS. The WSO, as presently conceived, will be constructed and operated with the same distributed philosophy. This will allow as many groups and countries to participate, each contributing as much as feasible but allowing multi-national participation. Although designed originally with a conservative approach, the WSO embodies some innovative ideas and will allow a world-class mission to be realized with a moderate budget.

Astrophysics and Space Science, 2014

ABSTRACT Space astronomy in the last 40 years has largely been done from spacecraft in low Earth ... more ABSTRACT Space astronomy in the last 40 years has largely been done from spacecraft in low Earth orbit (LEO) for which the technology is proven and delivery mechanisms are readily available. However, new opportunities are arising with the surge in commercial aerospace missions. We describe here one such possibility: deploying a small instrument on the Moon. This can be accomplished by flying onboard the Indian entry to the Google Lunar X PRIZE competition, Team Indus mission, which is expected to deliver a nearly 30 kgs of payloads to the Moon, with a rover as its primary payload. We propose to mount a wide-field far-UV (130–180 nm) imaging telescope as a payload on the Team Indus lander. Our baseline operation is a fixed zenith pointing but with the option of a mechanism to allow observations of different attitudes. Pointing towards intermediate ecliptic latitude (50∘ or above) ensures that the Sun is at least 40∘ off the line of sight at all times. In this position, the telescope can cover higher galactic latitudes as well as parts of Galactic plane. The scientific objectives of such a prospective are delineated and discussed.

Despite the spectrographic evidence for wind-driven mass loss from erupting dwarf novae, almost n... more Despite the spectrographic evidence for wind-driven mass loss from erupting dwarf novae, almost no visible shells surrounding these systems have ever been detected. Theory predicts that the white dwarfs in all dwarf novae must eventually accrete enough mass to undergo classical nova eruptions, but not a single dwarf nova has ever been shown to have undergone a classical nova eruption.

We present the fifth list with results of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS ... more We present the fifth list with results of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS therein, SAO - Special Astrophysical Observatory, Russia). The list is a result of follow-up spectroscopy conducted with the 2.2m CAHA and 4m Kitt Peak telescopes in 1999. The data of this snap-shot spectroscopy survey confirmed 166 emission-line objects out of 209 observed candidates and allowed

An international facility to store, catalogue and digitise photographic plates is under developme... more An international facility to store, catalogue and digitise photographic plates is under development at the Royal Observatory of Belgium in Uccle-Brussels. The creation of such a facility requires a well-organized effort and substantial resources. However, the cost is not exorbitantly high if one takes advantage of the new generation of commercial, photogrammetric, flatbed scanners, which use the latest CCD technology.

ESO ASTROPHYSICS SYMPOSIA, 2004

The World Space Observatory (WSO/UV) is a space project for an ultraviolet telescope which has to... more The World Space Observatory (WSO/UV) is a space project for an ultraviolet telescope which has to fulfill the needs and scientific requirements of a worldwide community. For this very reason, the project development is distributed among many countries, scientific institutes and companies. The technical requirements relevant for the AVO efficient performance have to be included and improved for the WSO/UV

Early-type dwarf galaxies dominate cluster populations, but their formation and evolutionary hist... more Early-type dwarf galaxies dominate cluster populations, but their formation and evolutionary histories are poorly understood. The ALFALFA (Arecibo Legacy Fast ALFA) blind survey is providing a census of HI in galaxies of all types in a range of environments. Here we report ALFALFA and follow-up H-alpha imaging results for Virgo Cluster early-type dwarfs at declinations between 4 and 16 degrees.

The Leo region offers a detailed view of several nearby groups of galaxies including Leo I at 10.... more The Leo region offers a detailed view of several nearby groups of galaxies including Leo I at 10.4 Mpc and another slightly more distant structure within the Local Supercluster (Leo II). Leo I is of particular interest because it contains both a large ring of intergalactic gas of unknown origin (the Leo Ring) as well as a long tidal stream

One of the principal drivers of the ALFALFA survey is the exploration of the dynamics of the Virg... more One of the principal drivers of the ALFALFA survey is the exploration of the dynamics of the Virgo cluster and its environs via the cataloguing of all of its gas-rich members and tracing disruptive events through the HI remnants they leave behind. The wide area coverage provided by ALFALFA is ideal for the study of extended source structures, and its

Earth Moon and Planets, 1998

P. BROWN1, MD CAMPBELL1, KJ ELLIS2, RL HAWKES3,*, J. JONES1, P. GURAL4 , D. BABCOCK3,5, C. BARNBA... more P. BROWN1, MD CAMPBELL1, KJ ELLIS2, RL HAWKES3,*, J. JONES1, P. GURAL4 , D. BABCOCK3,5, C. BARNBAUM6, RK BARTLETT7, M. BEDARD8, J. BEDIENT9, M. BEECH10, N. BROSCH11, S. CLIFTON12, M. CONNORS13, B. COOKE12, P. GOETZ14, ...

We present the fourth list with results of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS... more We present the fourth list with results of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS hereafter, SAO -- Special Astrophysical Observatory, Russia). The main goal of the project is the search for emission-line galaxies (ELG) in order to create a new deep sample of blue compact/HII galaxies (BCG) in a large sky area. Another important goal of this work is

High Energy, Optical, and Infrared Detectors for Astronomy III, 2008

The Position-Sensitive Detector (PSD) on base of GaAs photocathode and microchannel plate set has... more The Position-Sensitive Detector (PSD) on base of GaAs photocathode and microchannel plate set has been developed. PSD consists of thick semiconductor photocathode with quantum efficiency about 48% in the range of 4000-8000AA, two microchannel plates, and 16-electrode collector. The detector has spatial resolution of 20-30 microns for about 5 • 105 pixels, time resolution of 1 us and effective sensitivity

The Arecibo Galaxy Environment Survey (AGES) is one of several H I surveys utilizing the new Arec... more The Arecibo Galaxy Environment Survey (AGES) is one of several H I surveys utilizing the new Arecibo L-band Feed Array (ALFA) fitted to the 305-m radio telescope at Arecibo. a The survey is specifically designed to investigate various galactic environments to higher sensitivity, higher velocity resolution and higher spatial resolution than previous fully sampled, 21-cm multibeam surveys. The emphasis is on making detailed observations of nearby objects although the large system bandwidth (100 MHz) will allow us to quantify the H I properties over a large instantaneous velocity range. In this paper, we describe the survey and its goals and present the results from the precursor observations of a 5 × 1-deg 2 region containing the nearby (∼10 Mpc) NGC 628 group. We have detected all the group galaxies in the region including the low-mass (M HI ∼10 7 M ⊙) dwarf, dw0137+1541. The fluxes and velocities for these galaxies compare well with previously published data. There is no intragroup neutral gas detected down to a limiting column density of 2 × 10 18 cm −2. In addition to the group galaxies we have detected 22 galaxies beyond the NGC 628 group, nine of which are previously uncatalogued. We present the H I data for these objects and also SuperCOSMOS images for possible optical galaxies that might be associated with the H I signal. We have used V/V max analysis to model how many galaxies beyond 1000 km s −1 should be detected and compare this with our results. The predicted number of detectable galaxies varies depending on the H I mass function (HIMF) used in the analysis. Unfortunately the precursor survey area is too small to determine whether this is saying anything fundamental about the HIMF or simply highlighting the effect of low number statistics. This is just one of many questions that will be addressed by the complete AGES survey.