Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Astrophysics and Astronomy (11)
- Environmental Sciences (4)
- Life Sciences (2)
- Physics (2)
- Social and Behavioral Sciences (2)
-
- Sustainability (2)
- Agricultural and Resource Economics (1)
- Agriculture Law (1)
- Animal Sciences (1)
- Asian Studies (1)
- Biochemistry (1)
- Biochemistry, Biophysics, and Structural Biology (1)
- Biology (1)
- Chemistry (1)
- Education (1)
- Environmental Law (1)
- Environmental Policy (1)
- Higher Education (1)
- International and Area Studies (1)
- Law (1)
- Mathematics (1)
- Oil, Gas, and Energy (1)
- Public Affairs, Public Policy and Public Administration (1)
- Institution
- Keyword
-
- Galaxies: structure (7)
- Galaxies: ISM (5)
- Galaxies: spiral (5)
- Galaxies: dwarf (3)
- Galaxies: evolution (3)
-
- Galaxies: stellar content (2)
- ISM: structure (2)
- Sustainability (2)
- Catalogs (1)
- College students (1)
- Consciousness (1)
- Diabetes (1)
- Dispersion (1)
- Dust (1)
- Dust, extinction (1)
- Dust, extinctione (1)
- Dust: extinction (1)
- Dynamic equation (1)
- Electron emission (1)
- Electron microscopes (1)
- Electron microscopy (1)
- Electron or ion microscopes (1)
- Electron spectroscopy (1)
- Electron- or ion-diffraction tubes (1)
- Environmental magnetism (1)
- Factory farms (1)
- Field emission (1)
- GDH1 (1)
- Galaxies: active (1)
- Galaxies: distances and redshifts (1)
Articles 1 - 19 of 19
Full-Text Articles in Physical Sciences and Mathematics
Re-Storing The Earth: A Phenomenological Study Of Living Sustainably, Jessica B. Buckley
Re-Storing The Earth: A Phenomenological Study Of Living Sustainably, Jessica B. Buckley
Faculty Scholarship
Living sustainably evokes ideas of lived, bodily engagement with and perception of the earth. Yet, modern ways of thinking and speaking have slowly alienated the earth from consciousness. Using phenomenological methods, the author examines the experience of living sustainably, exploring her own background and the idea of restoring the earth to consciousness, before examining the lives of two students dedicated to living sustainably. Components of upholding the earth, in-volving humanity, perceiving differences in studying and embodying sustainability, and engaging in choices fill the experience of living sustainably.
Identification Of Disufide Bond Formation Between Mitoneet And Glutamate Dehydrogenase 1., Morgan Roberts, Jacquelyn Crail, Megan Laffoon, William Fernandez, Michael Menze, Mary Konkle
Identification Of Disufide Bond Formation Between Mitoneet And Glutamate Dehydrogenase 1., Morgan Roberts, Jacquelyn Crail, Megan Laffoon, William Fernandez, Michael Menze, Mary Konkle
Faculty Scholarship
MitoNEET is a protein that was identified as a drug target for diabetes, but its cellular function as well as its role in diabetes remains elusive. Protein pull-down experiments identified glutamate dehydrogenase 1 (GDH1) as a potential binding partner. GDH1 is a key metabolic enzyme with emerging roles in insulin regulation. MitoNEET forms a covalent complex with GDH1 through disulfide bond formation and acts as an activator. Proteomic analysis identified the specific cysteine residues that participate in the disulfide bond. This is the first report that effectively links mitoNEET to activation of the insulin regulator GDH1.
The Kalman Filter For Linear Systems On Time Scales, Martin Bohner, Nick Wintz
The Kalman Filter For Linear Systems On Time Scales, Martin Bohner, Nick Wintz
Faculty Scholarship
We introduce the Kalman filter for linear systems on time scales, which includes the discrete and continuous versions as special cases. When the system is also stochastic, we show that the Kalman filter is an observer that estimates the system when the state is corrupted by noisy measurements. Finally, we show that the duality of the Kalman filter and the Linear Quadratic Regulator (LQR) is preserved in their unification on time scales. A numerical example is provided.
Quantified H I Morphology – Vii. Star Formation And Tidal Influence On Local Dwarf H I Morphology., Benne W. Holwerda, N. Pirzkal, W. J. G. De Blok, S. -L. Blyth
Quantified H I Morphology – Vii. Star Formation And Tidal Influence On Local Dwarf H I Morphology., Benne W. Holwerda, N. Pirzkal, W. J. G. De Blok, S. -L. Blyth
Faculty Scholarship
Scale-invariant morphology parameters applied to atomic hydrogen maps (H i) of galaxies can be used to quantify the effects of tidal interaction or star formation on the interstellar matter (ISM). Here we apply these parameters, concentration, asymmetry, smoothness, Gini, M20, and the GM parameter, to two public surveys of nearby dwarf galaxies, the Very Large Array-ANGST and Local Irregulars That Trace Luminosity Extremes-The H i Nearby Galaxy Survey, to explore whether tidal interaction or the ongoing or past star formation is a dominant force shaping the H i disc of these dwarfs. Previously, H i morphological criteria were identified for …
X-Ray Nuclear Activity In S4g Barred Galaxies : No Link Between Bar Strength And Co-Occurrent Supermassive Black Hole Fueling., Mauricio Cisternas, Dimitri A. Gadotti, Johan H. Knapen, Taehyun Kim, Simon Diaz-Garcia, Eija Laurikainen, Heikki Salo, Omaira Gonzalez-Martin, Luis C. Ho, Bruce G. Elmegreen, Dennis Zaritsky, Kartik Sheth, E. Athanassoula, Albert Bosma, Sebastien Comeron, Santiago Erroz-Ferrer, Armando Gil De Paz, Joannah L. Hinz, Benne W. Holwerda, Jarkko Laine, Sharon Meidt, Karin Menendez-Delmestre, Trisha Mizusawa, Juan Carlos Munoz-Mateos, Michael W. Regan, Mark Seibert
X-Ray Nuclear Activity In S4g Barred Galaxies : No Link Between Bar Strength And Co-Occurrent Supermassive Black Hole Fueling., Mauricio Cisternas, Dimitri A. Gadotti, Johan H. Knapen, Taehyun Kim, Simon Diaz-Garcia, Eija Laurikainen, Heikki Salo, Omaira Gonzalez-Martin, Luis C. Ho, Bruce G. Elmegreen, Dennis Zaritsky, Kartik Sheth, E. Athanassoula, Albert Bosma, Sebastien Comeron, Santiago Erroz-Ferrer, Armando Gil De Paz, Joannah L. Hinz, Benne W. Holwerda, Jarkko Laine, Sharon Meidt, Karin Menendez-Delmestre, Trisha Mizusawa, Juan Carlos Munoz-Mateos, Michael W. Regan, Mark Seibert
Faculty Scholarship
Stellar bars can lead to gas inflow toward the center of a galaxy and stimulate nuclear star formation. However, there is no compelling evidence on whether they also feed a central supermassive black hole: by measuring the fractions of barred active and inactive galaxies, previous studies have yielded conflicting results. In this paper, we aim to understand the lack of observational evidence for bar-driven active galactic nucleus (AGN) activity by studying a sample of 41 nearby (d < 35 Mpc) barred galaxies from the Spitzer Survey for Stellar Structure in Galaxies. We use Chandra observations to measure nuclear 2–10 keV X-ray luminosities and estimate Eddington ratios, together with Spitzer 3.6 μm imaging to quantify the strength of the stellar bar in two independent ways: (1) from its structure, as traced by its ellipticity and boxiness, and (2) from its gravitational torque Qb, taken as the maximum ratio of the tangential force to the mean background radial force. In this way, rather than discretizing the presence of both stellar bars and nuclear activity, we are able to account for the continuum of bar strengths and degrees of AGN activity. We find nuclear X-ray sources in 31 out of 41 galaxies with median X-ray luminosity and Eddington ratio of LX = 4.3×1038 erg s−1 and Lbol/LEdd = 6.9×10−6, respectively, consistent with low-luminosity AGN activity. Including upper limits for those galaxies without nuclear detections, we find no significant correlation between any of the bar strength indicators and the degree of nuclear activity, irrespective of galaxy luminosity, stellar mass, Hubble type, or bulge size. Strong bars do not favor brighter or more efficient nuclear activity, implying that at least for the low-luminosity regime, supermassive black hole fueling is not closely connected to large-scale features.
Grass Fires—An Unlikely Process To Explain The Magnetic Properties Of Prairie Soils, Stephani A. Roman, William C. Johnson, Christoph Geiss
Grass Fires—An Unlikely Process To Explain The Magnetic Properties Of Prairie Soils, Stephani A. Roman, William C. Johnson, Christoph Geiss
Faculty Scholarship
It has been proposed that grass fires affect the magnetic properties of soils by combining generally reducing soil conditions with elevated temperatures. To explore this supposition, we analysed surface and subsurface samples from loessic soils and compared their differences in magnetic properties as a function of fire intensity. Fire intensity was established based on types of burnt vegetation, which ranged from low-intensity fires in short-grass areas to high-intensity fires in tall-grass and forested areas. We measured low-field magnetic susceptibility (χ), a common proxy for the abundance of magnetic minerals, frequency-dependent susceptibility (χFD), a proxy for …
Design And Implementation Of A Fs-Resolved Transmission Electron Microscope Based On Thermionic Gun Technology [Post-Print], L. Piazza, D. J. Masiel, T. Lagrange, B. W. Reed, Brett Barwick
Design And Implementation Of A Fs-Resolved Transmission Electron Microscope Based On Thermionic Gun Technology [Post-Print], L. Piazza, D. J. Masiel, T. Lagrange, B. W. Reed, Brett Barwick
Faculty Scholarship
In this paper, the design and implementation of a femtosecond-resolved ultrafast transmission electron microscope is presented, based on a thermionic gun geometry. Utilizing an additional magnetic lens between the electron acceleration and the nominal condenser lens system, a larger percentage of the electrons created at the cathode are delivered to the specimen without degrading temporal, spatial and energy resolution significantly, while at the same time maintaining the femtosecond temporal resolution. Using the photon-induced near field electron microscopy effect (PINEM) on silver nanowires the cross-correlation between the light and electron pulses was measured, showing the impact of the gun settings and …
On The Origin Of Lopsidedness In Galaxies As Determined From The Spitzer Survey Of Stellar Structure In Galaxies (S4g)., Dennis Zaritsky, Heikki Salo, Eija Laurikainen, Debra M. Elmegreen, E. Athanassoula, Albert Bosma, Sebastien Comeron, Santiago Erroz-Ferrer, Bruce G. Elmegreen, Dimitri A. Gadotti, Armando Gil De Paz, Joannah L. Hinz, Luis C. Ho, Benne W. Holwerda, Taehyun Kim, Johan H. Knapen, Jarkko Laine, Seppo Laine, Barry F. Madore, Sharon Meidt, Karin Menendez-Delmestre, Trisha Mizusawa, Juan Carlos Munoz-Mateos, Michael W. Regan, Mark Seibert, Kartik Sheth
On The Origin Of Lopsidedness In Galaxies As Determined From The Spitzer Survey Of Stellar Structure In Galaxies (S4g)., Dennis Zaritsky, Heikki Salo, Eija Laurikainen, Debra M. Elmegreen, E. Athanassoula, Albert Bosma, Sebastien Comeron, Santiago Erroz-Ferrer, Bruce G. Elmegreen, Dimitri A. Gadotti, Armando Gil De Paz, Joannah L. Hinz, Luis C. Ho, Benne W. Holwerda, Taehyun Kim, Johan H. Knapen, Jarkko Laine, Seppo Laine, Barry F. Madore, Sharon Meidt, Karin Menendez-Delmestre, Trisha Mizusawa, Juan Carlos Munoz-Mateos, Michael W. Regan, Mark Seibert, Kartik Sheth
Faculty Scholarship
We study the m = 1 distortions (lopsidedness) in the stellar components of 167 nearby galaxies that span a wide range of morphologies and luminosities. We confirm the previous findings of (1) a high incidence of lopsidedness in the stellar distributions, (2) increasing lopsidedness as a function of radius out to at least 3.5 exponential scale lengths, and (3) greater lopsidedness, over these radii, for galaxies of later type and lower surface brightness. Additionally, the magnitude of the lopsidedness (1) correlates with the character of the spiral arms (stronger arm patterns occur in galaxies with less lopsidedness), (2) is not …
Herschel Observations Of Edge-On Spirals (Heroes) I. Far-Infrared Morphology And Dust Mass Determination., J. Verstappen, J. Fritz, M. Baes, M. W. L. Smith, F. Allaert, S. Bianchi, J. A. D. L. Blommaert, G. De Geyter, I. De Looze, G. Gentile, K. D. Gordon, Benne W. Holwerda, S. Viaene, E. M. Xilouris
Herschel Observations Of Edge-On Spirals (Heroes) I. Far-Infrared Morphology And Dust Mass Determination., J. Verstappen, J. Fritz, M. Baes, M. W. L. Smith, F. Allaert, S. Bianchi, J. A. D. L. Blommaert, G. De Geyter, I. De Looze, G. Gentile, K. D. Gordon, Benne W. Holwerda, S. Viaene, E. M. Xilouris
Faculty Scholarship
Context. Edge-on spiral galaxies with prominent dust lanes provide us with an excellent opportunity to study the distribution and properties of the dust within them. The HEROES project was set up to observe a sample of seven large edge-on galaxies across various wavelengths for this investigation. Aims. Within this first paper, we present the Herschel observations and perform a qualitative and quantitative analysis on them, and we derive some global properties of the far infrared and submillimetre emission. Methods. We determine horizontal and vertical profiles from the Herschel observations of the galaxies in the sample and describe the morphology. Modified …
The Occulting Galaxy Pair Ugc 3995 : Dust Properties From Hst And Califa Data., Benne W. Holwerda, W. C. Keel
The Occulting Galaxy Pair Ugc 3995 : Dust Properties From Hst And Califa Data., Benne W. Holwerda, W. C. Keel
Faculty Scholarship
UGC 3995 is an interacting and occulting galaxy pair. UGC 3995B is a foreground face-on spiral and UGC 3995A a bright background spiral with an AGN. We present analysis of the dust in the disc of UGC 3995B based on archival Hubble Space Telescope (HST) WFPC2 and PPAK IFU data from the CALIFA survey’s first data release. From the HST F606W image, we construct an extinction map by modeling the isophotes of the background galaxy UGC 3995A and the resulting transmission through UGC 3995B. This extinction map of UGC 3995B shows several distinct spiral extinction features. The radial distribution of …
The Impact Of Bars On Disk Breaks As Probed By S4g Imaging., Juan Carlos Munoz-Mateos, Kartik Sheth, Armando Gil De Paz, Sharon Meidt, E. Athanassoula, Albert Bosma, Sebastien Comeron, Debra M. Elmegreen, Bruce G. Elmegreen, Santiago Erroz-Ferrer, Dimitri A. Gadotti, Joannah L. Hinz, Luis C. Ho, Benne W. Holwerda, Thomas H. Jarrett, Taehyun Kim, Johan H. Knapen, Jarkko Laine, Eija Laurikainen, Barry F. Madore, Karin Menendez-Delmestre, Trisha Mizusawa, Michael Regan, Heikki Salo, Eva Schinnerer, Mark Seibert, Ramin Skibba, Dennis Zaritsky
The Impact Of Bars On Disk Breaks As Probed By S4g Imaging., Juan Carlos Munoz-Mateos, Kartik Sheth, Armando Gil De Paz, Sharon Meidt, E. Athanassoula, Albert Bosma, Sebastien Comeron, Debra M. Elmegreen, Bruce G. Elmegreen, Santiago Erroz-Ferrer, Dimitri A. Gadotti, Joannah L. Hinz, Luis C. Ho, Benne W. Holwerda, Thomas H. Jarrett, Taehyun Kim, Johan H. Knapen, Jarkko Laine, Eija Laurikainen, Barry F. Madore, Karin Menendez-Delmestre, Trisha Mizusawa, Michael Regan, Heikki Salo, Eva Schinnerer, Mark Seibert, Ramin Skibba, Dennis Zaritsky
Faculty Scholarship
We have analyzed the radial distribution of old stars in a sample of 218 nearby face-on disks, using deep 3.6μm images from the Spitzer Survey of Stellar Structure in Galaxies. In particular, we have studied the structural properties of those disks with a broken or down-bending profile. We find that, on average, disks with a genuine single-exponential profile have a scale length and a central surface brightness which are intermediate to those of the inner and outer components of a down-bending disk with the same total stellar mass. In the particular case of barred galaxies, the ratio between the break …
Emission-Line Galaxies From The Hubble Space Telescope Probing Evolution And Reionization Spectroscopically (Pears) Grism Survey. Ii. The Complete Sample., N. Pirzkal, Barry Rothberg, Chun Ly, Sangeeta Malhotra, James E. Rhoads, Norman A. Grogin, Tomas Dahlen, Kai G. Noeske, Gerhardt R. Meurer, Jeremy R. Walsh, Nimish P. Hathi, Seth H. Cohen, Andrea Bellini, Benne W. Holwerda, Amber N. Straughn, Matthew Mechtley, Rogier A. Windhorst
Emission-Line Galaxies From The Hubble Space Telescope Probing Evolution And Reionization Spectroscopically (Pears) Grism Survey. Ii. The Complete Sample., N. Pirzkal, Barry Rothberg, Chun Ly, Sangeeta Malhotra, James E. Rhoads, Norman A. Grogin, Tomas Dahlen, Kai G. Noeske, Gerhardt R. Meurer, Jeremy R. Walsh, Nimish P. Hathi, Seth H. Cohen, Andrea Bellini, Benne W. Holwerda, Amber N. Straughn, Matthew Mechtley, Rogier A. Windhorst
Faculty Scholarship
We present a full analysis of the Probing Evolution And Reionization Spectroscopically (PEARS) slitess grism spectroscopic data obtained with the Advanced Camera for Surveys on board Hubble Space Telescope. PEARS covers fields within both the Great Observatories Origins Deep Survey (GOODS) North and South fields, making it ideal as a random survey of galaxies, as well as the availability of a wide variety of ancillary observations complemented by the spectroscopic results. Using the PEARS data, we are able to identify star-forming galaxies (SFGs) within the redshift volume 0 < z < 1.5. Star-forming regions in the PEARS survey are pinpointed independently of the host galaxy. This method allows us to detect the presence of multiple emission-line regions (ELRs) within a single galaxy. We identified a total of 1162 Hα, [O iii], and/or [O ii] emission lines in the PEARS sample of 906 galaxies to a limiting flux of ∼10−18 erg s−1 cm−2. The ELRs have also been compared to the properties of the host galaxy, including morphology, luminosity, and mass. From this analysis, we find three key results: (1) the computed line luminosities show evidence of a flattening in the luminosity function with increasing redshift; (2) the star-forming systems show evidence of complex morphologies with star formation occurring predominantly within one effective (half-light) radius. However, the morphologies show no correlation with host stellar mass. (3) Also, the number density of SFGs with M∗ 109 M decreases by an order of magnitude at z 0.5 relative to the number at 0.5 < z < 0.9, supporting the argument of galaxy downsizing.
Vlt/Vimos Observations Of An Occulting Galaxy Pair : Redshifts And Effective Extinction Curve., Benne W. Holwerda, T. Boker, J. J. Dalcanton, W. C. Keel, R. S. De Jong
Vlt/Vimos Observations Of An Occulting Galaxy Pair : Redshifts And Effective Extinction Curve., Benne W. Holwerda, T. Boker, J. J. Dalcanton, W. C. Keel, R. S. De Jong
Faculty Scholarship
We present Very Large Telescope/Visible Multiobject Spectrograph Integral Field Unit observations of an occulting galaxy pair previously discovered in Hubble Space Telescope (HST) observations. The foreground galaxy is a low-inclination spiral disc, which causes clear attenuation features seen against the bright bulge and disc of the background galaxy. We find redshifts of z = 0.064 ± 0.003 and 0.065 for the foreground and background galaxy, respectively. This relatively small difference does not rule out gravitational interaction between the two galaxies. Emission line ratios point to a star-forming, not active galactic nuclei dominated foreground galaxy. We fit the Cardelli, Clayton and …
China And Central Asia: A Significant New Energy Nexus, Fakhmiddin Fazilov, Xiangming Chen
China And Central Asia: A Significant New Energy Nexus, Fakhmiddin Fazilov, Xiangming Chen
Faculty Scholarship
China now accounts for almost 20 percent of the world’s energy consumption and its demand is still growing at high speed. In order to keep up with the expanding industry China turns to Central Asia with ambitious gas line projects and considers countries such as Kazakhstan, Turkmenistan and Uzbekistan to be key factors in its energy security nexus.
Testing Galaxy Formation Models With The Ghosts Survey : The Color Profile Of M81'S Stellar Halo., Antonela Monachesi, Eric F. Bell, David J. Radburn-Smith, Marija Vlajic, Roelof S. De Jong, Jeremy Bailin, Julianne J. Dalcanton, Benne W. Holwerda, David Streich
Testing Galaxy Formation Models With The Ghosts Survey : The Color Profile Of M81'S Stellar Halo., Antonela Monachesi, Eric F. Bell, David J. Radburn-Smith, Marija Vlajic, Roelof S. De Jong, Jeremy Bailin, Julianne J. Dalcanton, Benne W. Holwerda, David Streich
Faculty Scholarship
We study the properties of the stellar populations in M81’s outermost part, which hereafter we will call the stellar halo, using Hubble Space Telescope (HST) Advanced Camera for Surveys observations of 19 fields from the GHOSTS survey. The observed fields probe the stellar halo out to a projected distance of ∼50 kpc from the galactic center. Each field was observed in both F606W and F814W filters. The 50% completeness levels of the color–magnitude diagrams (CMDs) are typically at 2 mag below the tip of the red giant branch (TRGB). Fields at distances closer than 15 kpc show evidence of disk-dominated …
The Opacity Of Spiral Galaxy Disks : Ix. Dust And Gas Surface Densities., Benne W. Holwerda, R. J. Allen, W. J. G. De Blok, A. Bouchard, R. A. Gonzalez-Lopezlira, P. C. Van Der Kruit, A. Leroy
The Opacity Of Spiral Galaxy Disks : Ix. Dust And Gas Surface Densities., Benne W. Holwerda, R. J. Allen, W. J. G. De Blok, A. Bouchard, R. A. Gonzalez-Lopezlira, P. C. Van Der Kruit, A. Leroy
Faculty Scholarship
Our aim is to explore the relation between gas, atomic and molecular, and dust in spiral galaxies. Gas surface densities are from atomic hydrogen and CO line emission maps. To estimate the dust content, we use the disk opacity as inferred from the number of distant galaxies identified in twelve HST/WFPC2 fields of ten nearby spiral galaxies. The observed number of distant galaxies is calibrated for source confusion and crowding with artificial galaxy counts and here we verify our results with sub-mm surface brightnesses from archival Herschel-SPIRE data. We find that the opacity of the spiral disk does not correlate …
Sustainable Production Of Swine: Putting Lipstick On A Pig?, Michelle B. Nowlin
Sustainable Production Of Swine: Putting Lipstick On A Pig?, Michelle B. Nowlin
Faculty Scholarship
No abstract provided.
Galaxy Zoo : A Catalog Of Overlapping Galaxy Pairs For Dust Studies., William C. Keel, Anna M. Manning, Benne W. Holwerda, Massimo Mezzoprete, Chris J. Lintott, Kevin Schawinski, Pamela Gay, Karen L. Masters
Galaxy Zoo : A Catalog Of Overlapping Galaxy Pairs For Dust Studies., William C. Keel, Anna M. Manning, Benne W. Holwerda, Massimo Mezzoprete, Chris J. Lintott, Kevin Schawinski, Pamela Gay, Karen L. Masters
Faculty Scholarship
Analysis of galaxies with overlapping images offers a direct way to probe the distribution of dust extinction and its effects on the background light. We present a catalog of 1990 such galaxy pairs selected from the Sloan Digital Sky Survey (SDSS) by volunteers of the Galaxy Zoo project. We highlight subsamples which are particularly useful for retrieving such properties of the dust distribution as UV extinction, the extent perpendicular to the disk plane, and extinction in the inner parts of disks. The sample spans wide ranges of morphology and surface brightness, opening up the possibility of using this technique to …
Femtosecond Photoelectron Point Projection Microscope, Erik Quinonez, Jonathan Handali, Brett Barwick
Femtosecond Photoelectron Point Projection Microscope, Erik Quinonez, Jonathan Handali, Brett Barwick
Faculty Scholarship
By utilizing a nanometer ultrafast electron source in a point projection microscope we demonstrate that images of nanoparticles with spatial resolutions of the order of 100 nanometers can be obtained. The duration of the emission process of the photoemitted electrons used to make images is shown to be of the order of 100 fs using an autocorrelation technique. The compact geometry of this photoelectron point projection microscope does not preclude its use as a simple ultrafast electron microscope, and we use simple analytic models to estimate temporal resolutions that can be expected when using it as a pump-probe ultrafast electron …