Near Infrared Imaging of the Hubble Deep Field with The Keck Telescope

Two deep K-band ($2.2 \mu m$) images, with point-source detection limits of $K=25.2$ mag (one sigma), taken with the Keck Telescope in subfields of the Hubble Deep Field, are presented and analyzed. A sample of objects to K=24 mag is constructed and $V_{606}-I_{814}$ and $I_{814}-K$ colors are measured. By stacking visually selected objects, mean $I_{814}-K$ colors can be measured to very faint levels; the mean $I_{814}-K$ color is constant with apparent magnitude down to $V_{606}=28$ mag.Comment: Replaced with slightly revised source positions and corrected V-I magnitudes (which were incorrect in the Tables and Figure 5). 18 pages. The data are publicly available at http://www.cco.caltech.edu/~btsoifer/hdf.html along with a high-resolution version of Fig.

Improved induction of anti-melanoma T cells by adenovirus-5/3 fiber modification to target human DCs

To mount a strong anti-tumor immune response, non T cell inflamed (cold) tumors may require combination treatment encompassing vaccine strategies preceding checkpoint inhibition. In vivo targeted delivery of tumor-associated antigens (TAA) to dendritic cells (DCs), relying on the natural functions of primary DCs in situ, represents an attractive vaccination strategy. In this study we made use of a full-length MART-1 expressing C/B-chimeric adenoviral vector, consisting of the Ad5 capsid and the Ad3 knob (Ad5/3), which we previously showed to selectively transduce DCs in human skin and lymph nodes. Our data demonstrate that chimeric Ad5/3 vectors encoding TAA, and able to target human DCs in situ, can be used to efficiently induce expansion of functional tumor-specific CD8⁺ effector T cells, either from a naïve T cell pool or from previously primed T cells residing in the melanoma-draining sentinel lymph nodes (SLN). These data support the use of Ad3-knob containing viruses as vaccine vehicles for in vivo delivery. "Off-the-shelf" DC-targeted Ad vaccines encoding TAA could clearly benefit future immunotherapeutic approaches

The IRAS bright galaxy sample. V. Multibeam photometry of galaxies with L(IR) ⩾ 10^(11) L_☉

Forty-seven galaxies from the IRAS Bright Galaxy Sample with infrared luminosities L_(IR)⩾ 10^(11) L_☉ have been measured at 1.3, 1.65, and 2.2 µm with beam diameters of 17", 33", and 55". These measurements, combined with 5" and 10" observations presented in an earlier paper, provide an opportunity to study the spatial distribution of the near-infrared emission in luminous IRAS galaxies. It is found that the unusually red near-infrared colors known previously for many of these galaxies are confined to the nuclear regions, whereas the outer disk regions have near-infrared colors essentially appropriate for a normal stellar population. Since dust reddening and emission are required to explain the unusual nuclear colors, it follows that the observed effects of dust in these galaxies are also confined primarily to the nuclei. Thus, it is probable that the far-infrared emission, the bulk of the entire luminosity in infrared luminous galaxies, is highly concentrated about the nuclei, and that the physical processes responsible for the unusual properties of infrared luminous galaxies tend to occur within the central regions, with diameters ≾1-3 kpc. The nuclei are found to have considerably higher 2.2 µm luminosities than are found in classical “starburst” nuclei, implying that infrared luminous galaxies are characterized by extremely high radiation densities in their central regions, presumably due to intense star formation activity and/or the presence of a dust-enshrouded quasar. However, the nuclei of the galaxies studied are typically not as luminous at 2.2 µm as classical Seyfert nuclei, which may be partly attributable to extinction from dust at near-infrared wavelengths, particularly for those sources in the sample that have been identified in the literature as having Seyfert nuclei. Finally, the large diameter beam measurements are used to obtain estimates of the total near-infrared emission. It is found that, since most of the infrared luminosity is coming from the nuclei, the global near-infrared properties of infrared luminous galaxies are not good tracers of infrared activity. Also, the contribution from the observed stellar emission to the total observed luminosity is found to be ≾25% for most of the galaxies in the sample, considerably smaller than the value for typical low-luminosity spiral galaxies

Observations of Rapid Disk-Jet Interaction in the Microquasar GRS 1915+105

We present evidence that ~ 30 minute episodes of jet formation in the Galactic microquasar GRS 1915+105 may sometimes entirely be a superposition of smaller, faster phenomena. We base this conclusion on simultaneous X-ray and infrared observations in July 2002, using the Rossi X-ray Timing Explorer and the Palomar 5 meter telescope. On two nights, we observed quasi-periodic infrared flares from GRS 1915+105, each accompanied by a set of fast oscillations in the X-ray light curve (indicating an interaction between the jet and accretion disk). In contrast to similar observations in 1997, we find that the duration of each X-ray cycle matches the duration of its accompanying infrared flare, and we observed one instance in which an isolated X-ray oscillation occurred at the same time as a faint infrared "subflare" (of duration ~ 150 seconds) superimposed on one of the main flares. From these data, we are able to conclude that each X-ray oscillation had an associated faint infrared flare and that these flares blend together to form, and entirely comprise, the ~ 30 minute events we observed. Part of the infrared emission in 1997 also appears to be due to superimposed small flares, but it was overshadowed by infrared-bright ejections associated with the appearance of a sharp "trigger" spike in each X-ray cycle that were not present in 2002. We also study the evolution of the X-ray spectrum and find significant differences in the high energy power law component, which was strongly variable in 1997 but not in 2002. Taken together, these observations reveal the diversity of ways in which the accretion disk and jet in black hole systems are capable of interacting and solidify the importance of the trigger spike for large ejections to occur on ~ 30 minute timescales in GRS 1915+105.Comment: 17 pages, 9 figures; accepted for publication in The Astrophysical Journa

Visualizing Spacetime Curvature via Frame-Drag Vortexes and Tidal Tendexes III. Quasinormal Pulsations of Schwarzschild and Kerr Black Holes

In recent papers, we and colleagues have introduced a way to visualize the full vacuum Riemann curvature tensor using frame-drag vortex lines and their vorticities, and tidal tendex lines and their tendicities. We have also introduced the concepts of horizon vortexes and tendexes and 3-D vortexes and tendexes (regions where vorticities or tendicities are large). Using these concepts, we discover a number of previously unknown features of quasinormal modes of Schwarzschild and Kerr black holes. These modes can be classified by mode indexes (n,l,m), and parity, which can be electric [(-1)^l] or magnetic [(-1)^(l+1)]. Among our discoveries are these: (i) There is a near duality between modes of the same (n,l,m): a duality in which the tendex and vortex structures of electric-parity modes are interchanged with the vortex and tendex structures (respectively) of magnetic-parity modes. (ii) This near duality is perfect for the modes' complex eigenfrequencies (which are well known to be identical) and perfect on the horizon; it is slightly broken in the equatorial plane of a non-spinning hole, and the breaking becomes greater out of the equatorial plane, and greater as the hole is spun up; but even out of the plane for fast-spinning holes, the duality is surprisingly good. (iii) Electric-parity modes can be regarded as generated by 3-D tendexes that stick radially out of the horizon. As these "longitudinal," near-zone tendexes rotate or oscillate, they generate longitudinal-transverse near-zone vortexes and tendexes, and outgoing and ingoing gravitational waves. The ingoing waves act back on the longitudinal tendexes, driving them to slide off the horizon, which results in decay of the mode's strength. (iv) By duality, magnetic-parity modes are driven in this same manner by longitudinal, near-zone vortexes that stick out of the horizon. [Abstract abridged.]Comment: 53 pages with an overview of major results in the first 11 pages, 26 figures. v2: Very minor changes to reflect published version. v3: Fixed Ref

High PrEP uptake and objective longitudinal adherence among HIV-exposed women with personal or partner plans for pregnancy in rural Uganda: A cohort study

Background In Uganda, fertility rates and adult HIV prevalence are high, and many women conceive with partners living with HIV. Pre-exposure prophylaxis (PrEP) reduces HIV acquisition for women and, therefore, infants. We developed the Healthy Families-PrEP intervention to support PrEP use as part of HIV prevention during periconception and pregnancy periods. We conducted a longitudinal cohort study to evaluate oral PrEP use among women participating in the intervention. Methods and findings We enrolled HIV–negative women with plans for pregnancy with a partner living, or thought to be living, with HIV (2017 to 2020) to evaluate PrEP use among women participating in the Healthy Families-PrEP intervention. Quarterly study visits through 9 months included HIV and pregnancy testing and HIV prevention counseling. PrEP was provided in electronic pillboxes, providing the primary adherence measure (“high” adherence when pillbox was opened ≥80% of days). Enrollment questionnaires assessed factors associated with PrEP use. Plasma tenofovir (TFV) and intraerythrocytic TFV-diphosphate (TFV-DP) concentrations were determined quarterly for women who acquired HIV and a randomly selected subset of those who did not; concentrations TFV ≥40 ng/mL and TFV-DP ≥600 fmol/punch were categorized as “high.” Women who became pregnant were initially exited from the cohort by design; from March 2019, women with incident pregnancy remained in the study with quarterly follow-up until pregnancy outcome. Primary outcomes included (1) PrEP uptake (proportion who initiated PrEP); and (2) PrEP adherence (proportion of days with pillbox openings during the first 3 months following PrEP initiation). We used univariable and multivariable-adjusted linear regression to evaluate baseline predictors selected based on our conceptual framework of mean adherence over 3 months. We also assessed mean monthly adherence over 9 months of follow-up and during pregnancy. We enrolled 131 women with mean age 28.7 years (95% CI: 27.8 to 29.5). Ninety-seven (74%) reported a partner with HIV and 79 (60%) reported condomless sex. Most women (N = 118; 90%) initiated PrEP. Mean electronic adherence during the 3 months following initiation was 87% (95% CI: 83%, 90%). No covariates were associated with 3-month pill-taking behavior. Concentrations of plasma TFV and TFV-DP were high among 66% and 47%, 56% and 41%, and 45% and 45% at months 3, 6, and 9, respectively. We observed 53 pregnancies among 131 women (1-year cumulative incidence 53% [95% CI: 43%, 62%]) and 1 HIV-seroconversion in a non-pregnant woman. Mean pillcap adherence for PrEP users with pregnancy follow-up (N = 17) was 98% (95% CI: 97%, 99%). Study design limitations include lack of a control group. Conclusions Women in Uganda with PrEP indications and planning for pregnancy chose to use PrEP. By electronic pillcap, most were able to sustain high adherence to daily oral PrEP prior to and during pregnancy. Differences in adherence measures highlight challenges with adherence assessment; serial measures of TFV-DP in whole blood suggest 41% to 47% of women took sufficient periconception PrEP to prevent HIV. These data suggest that women planning for and with pregnancy should be prioritized for PrEP implementation, particularly in settings with high fertility rates and generalized HIV epidemics. Future iterations of this work should compare the outcomes to current standard of care

Collecting, analyzing and archiving of ground based infrared solar spectra obtained from several locations

The infrared solar spectrum as observed from the ground under high resolution contains thousands of absorption lines. The majority of these lines are due to compounds that are present in the Earth's atmosphere. Ground based infrared solar spectra contain information concerning the composition of the atmosphere at the time the spectra were obtained. The objective of this program is to record solar spectra from various ground locations, and to analyze and archive these spectra. The analysis consists of determining, for as many of the absorption lines as possible, the molecular species responsible for the absorption, and to verify that current models of infrared transmission match the observed spectra. Archiving is an important part of the program, since a number of the features in the spectra have not been identified. At some later time, when the features are identified, it will be possible to determine the amount of that compound that was present in the atmosphere at the time the spectrum was taken

The near-infrared morphology of ultraluminous infrared galaxies

Near-infrared images at 1.25 μm, 1.65 μm, and 2.2 μm have been obtained of nine galaxies from the IRAS Bright Galaxy Sample with infrared luminosities L_(IR) ≥ 10^(12) L_☉. Two of the 2.2 μm images reveal previously undetected double nuclei, increasing the number of close double nuclei known for this sample from two to four. For three of these four sources, the colors of both nuclei are substantially different from those of normal spiral galaxies, indicating that the high activity state in high-luminosity mergers tends to occur in both nuclei. Three sources show 2.2 μm emission that is more centrally concentrated than the emission at 1.3 μm, a result that can be explained as the effects of dust emission and/or extinction or, alternatively, as the result of direct emission at 2.2 μm from the accretion disk of a central active galactic nucleus. Implications of these results for the model that galaxy collisions lead to quasar formation are briefly discussed. Finally, from the frequency and separation of the double nucleus sources, the lifetime of the ultraluminous phase of galaxies is estimated to be ~ 4 x 10^8 yr

The IRAS Bright Galaxy Sample. III. 1-10 µm observations and coadded IRAS data for galaxies with L_(IR) ⩾ 10^(11) L⊙

Galaxies from the IRAS Bright Galaxy Sample with infrared luminosities L_(IR) ⩾ 10^(11) L⊙ have been measured at 1.3, 1.6, 2.2, 3.7, and 10 µm. In addition, coadded IRAS measurements at all four IRAS bands have been obtained. It is found that an increase in the total infrared luminosity above L_(IR) ⩾ 10^(11) L⊙ is correlated with increased emission from hot dust with characteristic temperatures ~800 K contributing a substantial fraction of the 2.2 and 3.7 µm emission. This hot dust emission appears to “turn on” at luminosities of roughly 10^(11) L⊙. The far-infrared emission cannot be modeled with a single dust temperature, but requires a cold (T~30-50 K) component coupled with a warmer (T≳70 K) component. Although the relative contribution from the cold component decreases with increasing luminosity, the temperature of the warmer component is independent of luminosity. The f_v (12 µm)/f_v (25 µm) ratios for the galaxies in this sample are small compared with other extragalactic objects, indicating that the radiation at 12 and 25 µm is dominated by emission from large dust grains radiating at high temperatures, rather than PAHs. The spatial distribution of the 10 µm emission indicates a substantial extended component for most of the galaxies in this sample, implying that star-formation processes contribute significantly to the luminosities. However, one-third of the galaxies have exponential scale sizes characteristic of compact sources, and half of the galaxies have 10 µm emission consistent with a contribution of 50% or more from a central point source