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1. Optimizing linewidth measurements for a low-scatter Baryonic Tully-Fisher Relation

   Ball, C.; Haynes, M. P.; Gande, A. (January 2021, American Astronomical Society meeting)

   null (Ed.)

   The Arecibo Pisces-Perseus Supercluster Survey (APPSS) aims to observationally measure the dark matter mass density of Pisces-Perseus by detecting the peculiar velocities of galaxies falling onto the supercluster. To do this, APPSS will measure galaxies' distances using the Baryonic Tully Fisher Relation (BTFR), which relates a galaxy's baryonic mass and rotational velocity. Recovering the signature of infall as robustly as possible requires a careful choice of rotational velocity measurement, as the use of various velocity definitions changes the scatter and systematics of the relation. We introduce and compare multiple automated methods for measuring a galaxy's rotational velocity using its unresolved line profile. The velocities discussed include global HI profile width measures commonly reported in large surveys, velocity widths derived from best-fit parametrizations to profiles, and velocity widths derived using more novel methods including the spectral line's curve of growth and neural network-derived velocities which incorporate information about the profile's width and shape. We compare these velocity measures by finding best-fit BTFR relations for two samples of galaxies - the SPARC sample and a selected sample of gas-dominated ALFALFA galaxies (Papastergis et al. 2016). With these best-fit BTFRs, we compare intrinsic scatters and residual correlations with source properties to investigate how velocity choice affects the absolute and systematic uncertainties of BTFR-derived galaxy distances. This research is supported by NSF/AST-1714828 and the Brinson Foundation. 

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2. From “good” distances to intriguing results: A Baryonic Tully-Fisher Relation from galaxies with primary distances

   Letai, J.; Haynes, M.; Gomez Barrientos, J.; Jones, M. (January 2021, American Astronomical Society meeting)

   null (Ed.)

   We present our work on constructing a template Baryonic Tully-Fisher Relation (BTFR) from galaxies in the local universe that have primary distances. We utilize HI 21 cm line data from the complete Arecibo Legacy Fast ALFA (ALFALFA) survey and the digital HI archive from Springob et al. 2005; we also use photometry from the Sloan Digital Sky Survey (SDSS) and the NASA Sloan Atlas (NSA) MANGA v1_0_2 database; lastly, we have also made use of the Extragalactic Distance Database (EDD) for identifying galaxies with primary distances. After cross-matching the galaxies in these catalogues, we identify some 144 galaxies which meet our requirements for having all the necessary HI and photometry data, having primary distances, residing within 30 Mpc, and having low enough uncertainties to be considered reliable data points. An important trait of this data set is the prominence of low-mass, low-luminosity dwarves. Notably, we find the values for the slope, intercept and intrinsic scatter of the relation to be around 2.3, 4.8, and 0.4, respectively. Further, while unresolved velocity widths have historically produced shallower slopes, and while the BTFR has been shown to have a higher intrinsic scatter for low-mass galaxies, these precedents are not enough to explain the deviation of our data from the “standard” values of the BTFR. This work therefore raises several questions about why this discrepancy exists, how it can be resolved, and what we can learn from it. The authors would like to acknowledge the support of NSF/AST-1714828 and the Brinson Foundation. 

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3. The Arecibo Pisces-Perseus Supercluster Survey: Characteristics of the APPSS Galaxy Population

   Montalvo, B.; Haynes, M. P.; Team, Undergraduate Alfalfa (January 2020, American Astronomical Society meeting)

   The Arecibo Pisces-Perseus Supercluster Survey(APPSS) aims to measure the infall and mass density along the PPS filament using red-shift independent distances obtained from the Baryonic Tully-Fisher Relation (BTFR). We will combine photometric data from the Sloan Digital Sky Survey with HI line spectroscopy obtained with the Arecibo telescope to derive BTFR distances and peculiar velocities over the PPS volume and its immediate foreground and background. To supplement the ALFALFA detections in the PPS volume, we have conducted new HI line observations with the Arecibo L-band Wide receiver system of blue, low surface brightness galaxies identified by their photometric properties in the Sloan Digital Sky Survey (SDSS). These targets are predicted to lie in the PPS volume but with HI masses of 8.0 < log HI mass < 9.0, putting them below the ALFALFA detection limit at that distance. We compare a preliminary sample of 634 galaxies detected as part from the APPSS survey with the main ALFALFA survey and other public catalogs of local galaxies, confirming that the new APPSS HI line detections are rotation-dominated, HI bearing galaxies with low stellar mass. Nearly all are star-forming, bluer, and of lower surface brightness, extinction and metallicity than optically selected samples. Preliminary BTFRs were calculated for both APPSS and ALFALFA galaxies and compared with BTFRs of simulated galaxies similar to those found in APPSS and ALFALFA using simulations such as IllustrisTNG (see poster by J. Borden). This work has been supported by NSF/AST-1714828 and the Brinson Foundation. 

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4. A Local Baryonic Tully-Fisher Relation from IllustrisTNG

   Borden, J. T.; Jones, M. G.; Haynes, M. P. (January 2020, American Astronomical Society meeting)

   The Pisces-Perseus Supercluster (PPS) offers a convenient, accessible environment for the study of large scale structure in the local universe. The Arecibo Pisces-Perseus Supercluster Survey (APPSS) seeks to observe the infall of galaxies toward the main filament of the PPS which is nearly perpendicular to our line of sight. Tracing such infall reveals valuable information about the gravitational field - and thus mass distribution - of the PPS. However, obtaining accurate measurements of such deviation from smooth Hubble flow requires redshift-independent distance measurements. The baryonic Tully-Fisher relation (BTFR) offers an appealing solution in the distance regime of the PPS, but while the high-mass end of this relation boasts a tight correlation, the low-mass end - where the APPSS sample lies - shows considerably more scatter. We use the magnetohydrodynamical simulations of IllustrisTNG to examine a template BTFR in an attempt to better understand the error budget of, and identify systematic scatter within, the BTFR as it corresponds to the APPSS sample of galaxies. We find the low mass scatter of the simulated BTFR to be populated predominantly by highly gas dominated, low surface brightness galaxies with colors less blue than typical. This unusually quiescent subset of galaxies appears to share systematically inefficient star formation, with very high gas depletion timescales that deviate rapidly from an otherwise gradual trend apparent throughout the rest of the galaxy population. This subset of inefficiently star forming galaxies tends to decrease the slope of the BTFR at low masses, an effect that lies in contrast to the steepening of the BTFR generally expected in this mass regime. Further work is needed to determine if this collection of galaxies is physically motivated or is instead a finite resolution effect of the simulation. This work is supported by NSF/AST-1714828 to MPH. 

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5. 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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