IPAC Image Processing and Data Archiving for the Palomar Transient Factory

The Palomar Transient Factory (PTF) is a multiepochal robotic survey of the northern sky that acquires data for the scientific study of transient and variable astrophysical phenomena. The camera and telescope provide for wide-field imaging in optical bands. In the five years of operation since first light on 2008 December 13, images taken with Mould-R and SDSS-g′ camera filters have been routinely acquired on a nightly basis (weather permitting), and two different Hα filters were installed in 2011 May (656 and 663 nm). The PTF image-processing and data-archival program at the Infrared Processing and Analysis Center (IPAC) is tailored to receive and reduce the data, and, from it, generate and preserve astrometrically and photometrically calibrated images, extracted source catalogs, and co-added reference images. Relational databases have been deployed to track these products in operations and the data archive. The fully automated system has benefited by lessons learned from past IPAC projects and comprises advantageous features that are potentially incorporable into other ground-based observatories. Both off-the-shelf and in-house software have been utilized for economy and rapid development. The PTF data archive is curated by the NASA/IPAC Infrared Science Archive (IRSA). A state-of-the-art custom Web interface has been deployed for downloading the raw images, processed images, and source catalogs from IRSA. Access to PTF data products is currently limited to an initial public data release (M81, M44, M42, SDSS Stripe 82, and the Kepler Survey Field). It is the intent of the PTF collaboration to release the full PTF data archive when sufficient funding becomes available

The Zwicky Transient Facility: Data Processing, Products, and Archive

The Zwicky Transient Facility (ZTF) is a new robotic time-domain survey currently in progress using the Palomar 48-inch Schmidt Telescope. ZTF uses a 47 square degree field with a 600 megapixel camera to scan the entire northern visible sky at rates of ~3760 square degrees/hour to median depths of g ~ 20.8 and r ~ 20.6 mag (AB, 5sigma in 30 sec). We describe the Science Data System that is housed at IPAC, Caltech. This comprises the data-processing pipelines, alert production system, data archive, and user interfaces for accessing and analyzing the products. The realtime pipeline employs a novel image-differencing algorithm, optimized for the detection of point source transient events. These events are vetted for reliability using a machine-learned classifier and combined with contextual information to generate data-rich alert packets. The packets become available for distribution typically within 13 minutes (95th percentile) of observation. Detected events are also linked to generate candidate moving-object tracks using a novel algorithm. Objects that move fast enough to streak in the individual exposures are also extracted and vetted. The reconstructed astrometric accuracy per science image with respect to Gaia is typically 45 to 85 milliarcsec. This is the RMS per axis on the sky for sources extracted with photometric S/N >= 10. The derived photometric precision (repeatability) at bright unsaturated fluxes varies between 8 and 25 millimag. Photometric calibration accuracy with respect to Pan-STARRS1 is generally better than 2%. The products support a broad range of scientific applications: fast and young supernovae, rare flux transients, variable stars, eclipsing binaries, variability from active galactic nuclei, counterparts to gravitational wave sources, a more complete census of Type Ia supernovae, and Solar System objects.Comment: 30 pages, 16 figures, Published in PASP Focus Issue on the Zwicky Transient Facility (doi: 10.1088/1538-3873/aae8ac

The Zwicky Transient Facility: System Overview, Performance, and First Results

The Zwicky Transient Facility (ZTF) is a new optical time-domain survey that uses the Palomar 48 inch Schmidt telescope. A custom-built wide-field camera provides a 47 deg 2 field of view and 8 s readout time, yielding more than an order of magnitude improvement in survey speed relative to its predecessor survey, the Palomar Transient Factory. We describe the design and implementation of the camera and observing system. The ZTF data system at the Infrared Processing and Analysis Center provides near-real-time reduction to identify moving and varying objects. We outline the analysis pipelines, data products, and associated archive. Finally, we present on-sky performance analysis and first scientific results from commissioning and the early survey. ZTF’s public alert stream will serve as a useful precursor for that of the Large Synoptic Survey Telescope

The Zwicky Transient Facility: System Overview, Performance, and First Results

The Zwicky Transient Facility (ZTF) is a new optical time-domain survey that uses the Palomar 48 inch Schmidt telescope. A custom-built wide-field camera provides a 47 deg^2 field of view and 8 s readout time, yielding more than an order of magnitude improvement in survey speed relative to its predecessor survey, the Palomar Transient Factory. We describe the design and implementation of the camera and observing system. The ZTF data system at the Infrared Processing and Analysis Center provides near-real-time reduction to identify moving and varying objects. We outline the analysis pipelines, data products, and associated archive. Finally, we present on-sky performance analysis and first scientific results from commissioning and the early survey. ZTF's public alert stream will serve as a useful precursor for that of the Large Synoptic Survey Telescope

Disseminated cysticercosis new observations, including CT scan findings and experience with treatment by praziquantel

Although the symptom complex of disseminated cysticercosis has been well recognized for over half a century, it is not clearly included in recent disease classifications. Three such patients are described whose main features were uncontrolled seizures, progressive dementia, behaviour disorder, muscular pseudohypertrophy, and a relative paucity of localizing neurological signs or signs of raised intracranial pressure. Radiographic calcification in muscles was not seen. A CT scan of the brain showed numerous small discrete lesions. Their attenuation density values were appreciably less than that of calcium and they enhanced slightly with contrast. Magnification revealed that these were scolices within cysticerci. There was no enhancement of the cyst wall and no pericystic oedema. CT scan of muscles showed similar cysticerci producing a 'honeycomb' appearance. This is the first CT demonstration of widely disseminated living cysticerci in brain and muscles. It was confirmed histologically. In the absence of palpable cysticerci, the clinical diagnosis can be missed, although no other disease in its full form presents in this manner. The symptoms are mainly caused by the space-occupying effect of the large number of cysticerci rather than by adjacent tissue swelling such as is seen in the presence of dying parasites. Praziquantel was ineffective and hazardous, causing some known and some previously unreported responses and reactions. All 3 patients died

Menkes Kinky Hair Syndrome: A Rare Neurodegenerative Disease

Menkes kinky hair disease is a rare X-linked recessive disease nearly exclusively affecting males who present at 2-3 months of age due to abnormal functioning of copper-dependent enzymes due to deficiency of copper. Here, we describe a completely worked-up case of a 4-month-old male infant with very typical history and radiological features confirmed by biochemical and trichoanalysis. The initially seen asymmetric cortical and subcortical T2 hyperintensities in cerebral and cerebellar hemispheres converted into symmetrical diffuse cerebral and predominantly cerebellar atrophy with uniform loss of both white and grey matter on follow-up MRI. Also, subdural hemorrhages of various sizes and different stages and tortuosity of larger proximal intracranial vessels with distal narrowing were identified. Ours is a completely worked-up proven case of Menkes kinky hair disease (MKHD) with history, electroencephalography, biochemical, trichoanalysis, and MRI findings. This is a good teaching case and shows importance of clinical examination and biochemistry as complimentary to MRI. Tortuous intracranial arteries with blocked major vessels are found only in this disease, thus stressing the value of MR Angiography in these patients

Coronary artery air embolism complicating a CT-guided percutaneous lung biopsy

Coronary arterial air embolism is an extremely rare but readily recognizable condition on computed tomography (CT) that may complicate a lung biopsy. We present an incidence of symptomatic air embolism into the right coronary artery during a percutaneous CT-guided lung biopsy that was successfully recognized during the procedure and managed accordingly. An active search for this complication should be made when the patient deteriorates on table and the usual complications (pneumothorax, vasovagal shock, etc.) are ruled out, as immediate resuscitative measures could be life-saving

Childhood Ataxia with Cerebral Hypomyelination (CACH) syndrome: a study of three siblings

We report a family of three siblings with Childhood Ataxia with Cerebral Hypomyelination. All the siblings presented with early onset cerebellar ataxia beginning around five years of age with mild mental retardation. MRI showed diffuse white matter signal changes in all three patients with cerebellar atrophy while the spectroscopy was abnormal only in the eldest who was the most severely affected. The cases are reported for their rarity as well as for an opportunity of observing this uncommon disease in its stages of evolution in three siblings