{
  "id": "2205.12949",
  "version": "v1",
  "published": "2022-05-25T17:54:39.000Z",
  "updated": "2022-05-25T17:54:39.000Z",
  "title": "High-Precision Redshifts for Type Ia Supernovae with the Nancy Grace Roman Space Telescope P127 Prism",
  "authors": [
    "Bhavin A. Joshi",
    "Louis-Gregory Strolger",
    "Russell E. Ryan, Jr.",
    "Alexei V. Filippenko",
    "Rebekah Hounsell",
    "Patrick L. Kelly",
    "Richard Kessler",
    "Phillip Macias",
    "Benjamin Rose",
    "Daniel Scolnic"
  ],
  "comment": "17 pages, 10 figures. Submitted to AAS journals. Comments welcome",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present results from simulating slitless spectroscopic observations with the Nancy Grace Roman Space Telescope's (Roman) Wide-Field Instrument (WFI) P127 prism spanning 0.75 $\\mu m$ to 1.8 $\\mu m$. We quantify the efficiency of recovered Type Ia supernovae (SNe Ia) redshifts, as a function of P127 prism exposure time, to guide planning for future observing programs with the Roman prism. Generating the two-dimensional dispersed images and extracting one-dimensional spectra is done with the slitless spectroscopy package pyLINEAR along with custom-written software. From the analysis of 1698 simulated SN Ia P127 prism spectra, we show the efficiency of recovering SN redshifts to $z\\lesssim3.0$, highlighting the exceptional sensitivity of the Roman P127 prism. Redshift recovery is assessed by setting a requirement of $\\sigma_z = (\\left|z - z_\\mathrm{true} \\right|)/(1+z) \\leq 0.01$. We find that 3 hr exposures are sufficient for meeting this requirement, for $\\gtrsim 50\\%$ of the sample of mock SNe Ia at $z\\approx2$ and within $\\pm5$ days of rest-frame maximum light in the optical. We also show that a 1 hr integration of Roman can achieve the same precision in completeness to a depth of $24.4 \\pm 0.06$ AB mag (or $z\\lesssim 1$). Implications for cosmological studies with Roman P127 prism spectra of SNe Ia are also discussed.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2022-05-25T17:54:39.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "nancy grace roman space telescope",
      "grace roman space telescope p127",
      "roman space telescope p127 prism",
      "type ia supernovae"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 17,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}