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1. Infall Profiles for Supercluster-scale Filaments

   https://doi.org/10.3847/1538-4357/ac815b  

   Odekon, Mary Crone ; Jones, Michael G. ; Graham, Lucas ; Kelley-Derzon, Jessica ; Halstead, Evan ( August 2022 , The Astrophysical Journal)

   We present theoretical expectations for infall toward supercluster-scale cosmological filaments, motivated by the Arecibo Pisces–Perseus Supercluster Survey (APPSS) to map the velocity field around the Pisces–Perseus Supercluster (PPS) filament. We use a minimum spanning tree applied to dark matter halos the size of galaxy clusters to identify 236 large filaments within the Millennium simulation. Stacking the filaments along their principal axes, we determine a well-defined, sharp-peaked velocity profile function that can be expressed in terms of the maximum infall rateV_maxand the distanceρ_maxbetween the location of maximum infall and the principal axis of the filament. This simple, two-parameter functional form is surprisingly universal across a wide range of linear mass densities.V_maxis positively correlated with the halo mass per length along the filament, andρ_maxis negatively correlated with the degree to which the halos are concentrated along the principal axis. We also assess an alternative, single-parameter method usingV₂₅, the infall rate at a distance of 25 Mpc from the axis of the filament. Filaments similar to the PPS have$V_{\max }=612\pm$116 km s⁻¹,${\rho }_{\max }=8.9\pm 2.1$Mpc, andV₂₅= 329 ± 68 km s⁻¹. We create mock observations to model uncertainties associated with viewing angle, lack of three-dimensional velocity information, limited sample size, and distance uncertainties. Our results suggest that it would be especially useful to measure infall for a larger sample of filaments to test our predictions for the shape of the infall profile and the relationships among infall rates and filament properties.

    

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2. Density and Velocity Profiles for Large-scale Cosmological Filaments

   Viscardi, T. ; Graham, L. ; Young, B. ; Crone-Odekon, M. ; Halstead, E. ; Jones, M. ; Team, APPSS ; Team, Undergraduate ALFALFA ; Team, ALFALFA ( January 2020 , American Astronomical Society meeting)

   In preparation for comparison with the Arecibo Pisces-Perseus Supercluster Survey (APPSS), we present the theoretically expected density and velocity profiles for large-scale (~ 50 Mpc) filaments from the Millennium simulation. We use an observationally-friendly method to identify filaments using the positions of large groups of galaxies, and average filaments together to find the typical structure of a filament in terms of cylindrical density profile and velocity infall profile. Both profiles can be fit by simple functions, but show a large scatter across the population of filaments. We are in the process of categorizing filaments to facilitate comparison with observations of specific filaments, like the Pisces-Perseus Supercluster filament. This work has been supported by NSF grant AST-1637339. 

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3. The Arecibo Pisces-Perseus Survey: Goals, data reduction, and initial results from declination strips 23 and 33

   Luna, Omar ; Craig, David W. ; Jones, Michael ; Haynes, Martha P. ; Koopmann, Rebecca ( January 2019 , American Astronomical Society, AAS Meeting #233, id.356.07)

   The Arecibo Pisces-Perseus Supercluster Survey (APPSS) attempts to detect the infall of galaxies onto the Pisces-Perseus Supercluster (PPS). The ALFALFA survey has greatly augmented the known redshifts across the region. APPSS sources will complement the ALFALFA sources, with the goal of building a large enough sample to make a high confidence measurement of infall and backflow onto the PSS filament via peculiar velocity estimates from the Tully-Fisher (TFR) and Baryonic Tully-Fisher (BTFR) relations. APPSS galaxies are selected using photometric data from the Sloan Digital Sky Survey (SDSS), aimed to detect low-mass, nearby gas-rich objects below the ALFALFA detection limit. The L-band wide receiver at Arecibo Observatory in Puerto Rico is used to obtain a five-minute ON-OFF measurement for each galaxy. Since the candidate galaxy redshifts are unknown, the receiver and spectrograph system are used in a search mode that spans the expected frequencies of HI emission from PPS galaxies. We will describe the goals, target selection, and data reduction process for the survey. Our collaboration has divided the PPS into two-degree wide declination strips for data reduction; we report preliminary results for strips 23 and 33. We have made the initial data reduction on more than 200 targets, and determined the systemic velocity, line width, integrated flux density, and HI mass for each candidate detection. We will compare results on our two declination strips, and point out interesting detections found along the way as examples of the data reduction process. This work has been supported by NSF grants AST-1211005 and AST-1637339. Publication: American Astronomical Society, AAS Meeting #233, id.356.07 Pub Date: January 2019 Bibcode: 2019AAS...23335607L 

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4. The Arecibo Pisces-Perseus Survey: Goals, data reduction, and initial results from declination strips 23 and 33

   Luna, Omar ; Craig, David W. ; Jones, Michael ; Haynes, Martha P. ; Koopmann, Rebecca ( January 2019 , American Astronomical Society, AAS Meeting)

   The Arecibo Pisces-Perseus Supercluster Survey (APPSS) attempts to detect the infall of galaxies onto the Pisces-Perseus Supercluster (PPS). The ALFALFA survey has greatly augmented the known redshifts across the region. APPSS sources will complement the ALFALFA sources, with the goal of building a large enough sample to make a high confidence measurement of infall and backflow onto the PSS filament via peculiar velocity estimates from the Tully-Fisher (TFR) and Baryonic Tully-Fisher (BTFR) relations. APPSS galaxies are selected using photometric data from the Sloan Digital Sky Survey (SDSS), aimed to detect low-mass, nearby gas-rich objects below the ALFALFA detection limit. The L-band wide receiver at Arecibo Observatory in Puerto Rico is used to obtain a five-minute ON-OFF measurement for each galaxy. Since the candidate galaxy redshifts are unknown, the receiver and spectrograph system are used in a search mode that spans the expected frequencies of HI emission from PPS galaxies. We will describe the goals, target selection, and data reduction process for the survey. Our collaboration has divided the PPS into two-degree wide declination strips for data reduction; we report preliminary results for strips 23 and 33. We have made the initial data reduction on more than 200 targets, and determined the systemic velocity, line width, integrated flux density, and HI mass for each candidate detection. We will compare results on our two declination strips, and point out interesting detections found along the way as examples of the data reduction process. This work has been supported by NSF grants AST-1211005 and AST-1637339. 

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5. The Arecibo Pisces-Perseus Supercluster Survey: Declination Strip 35

   McMichael, Chelsey ; Ribaudo, Joseph ; Koopmann, Rebecca A. ; Haynes, Martha P. ; APPSS Team, Undergraduate ALFALFA ( January 2018 , American Astronomical Society, AAS Meeting)

   The Arecibo Pisces-Perseus Supercluster Survey (APPSS) will provide strong observational constraints on the mass-infall rate onto the main filament of the Pisces-Perseus Supercluster. The survey data consist of HI emission-line spectra of cluster galaxy candidates, obtained primarily at the Arecibo Observatory (with ALFA as part of the ALFALFA Survey and with the L-Band Wide receiver as part of APPSS observations). Here we present the details of the data reduction process and spectral-analysis techniques used to determine if a galaxy candidate is at a velocity consistent with the Supercluster, as well as the detected HI-flux and rotational velocity of the galaxy, which will be used to estimate the corresponding HI-mass. We discuss the results of a preliminary analysis on a subset of the APPSS sample, corresponding to 98 galaxies located within ~1.5° of DEC = +35.0°, with 65 possible detections. We also highlight several interesting emission-line features and galaxies discovered during the reduction and analysis process and layout the future of the APPSS project. This work has been supported by NSF grants AST-1211005 and AST-1637339. 

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