Variability of Accreting White Dwarf Binaries and Other Compact Objects

Manuel Pichardo Marcano (Texas Tech University)

Liliana Rivera Sandoval & Thomas J. Maccarone

Compact Binaries Surveys

1- SCOVaS: Survey for Compact Objects and Variables

Pichardo Marcano et al. (2021a)

Pichardo Marcano et al. (in prep.)

 

 

 

2- TACOS: TESS AM CVn Outbursts Survey

Pichardo Marcano et al. (2021b)

Compact Binaries Surveys

X-ray unbiased search

SCOVaS: Survey for Compact Objects and Variables Stars

• HST Archive
• 7 Globular Clusters
• Many Exposures
• Different properties
  • Metallicity
  • Core-collapsed
  • Non core-collapse

SCOVaS: Survey for Studying Compact Objects and Variables

  

• Focus: Cataclysmic Variables (CVs) with HST
• First Unbiased Survey for CVs in Globular Clusters
  • X-ray faint CVs
  • Orbital Periods
• Spatial Distribution:
  • Looking at the dense Core of Clusters
  • Next: Search in the Outskirts
• Optical Counterpart X-ray/Radio Sources in GCs

Preliminary Results

NGC 6397

• WFPC-2
• March-April 2005:
  • 126 orbits
  • F814W, F606W and F336W
  • Exp time: 500-700 s

Preliminary Results

NGC 6397

• WFPC-2
• March-April 2005:
  • 126 orbits
  • F814W, F606W and F336W
  • Exp time: 500-700 s

A new candidate Redback Pulsar

HUGS catalogue. (Piotto et al. 2015, Nardiello et al. 2018)

Pichardo Marcano et al. (2021a)

X-ray

HST F336W

Radio

Zhao, [...], Pichardo Marcano,  et al. (2020)

A new candidate Redback MSP

Pichardo Marcano et. al (2021a)

• Porb 1.96 days
• Longest Porb for Redback in GCs
• Missed MSP in Pulsar Searchers

Blue Variables

Light Curves of Known CV Candidates

High and Low state?

Nova-like Candidate

Pichardo Marcano et. al (in prep)

U19

U21

Nova-like Candidate

First Magnetic He WD Candidate

Pichardo Marcano et. al (in prep)

Magnetic He WD

• V_rad > 100 km/s (MUSE)
• Not Detected in X-rays
• Rotation Period

  • 18.4 hours 

Pichardo Marcano et. al (in prep)

Pre-Cataclysmic Variable

Pichardo Marcano et. al (in prep)

Detached White Dwarf-Red Dwarf

• Not Detected in X-rays
• Potential P_orb

  • 5.21 hours 

Pichardo Marcano et. al (in prep)

Detached White Dwarf-Red Dwarf

NGC 6397

• Pipeline to find interesting objects:
  • CMD Position and Periodicity/Variability Searches
• We were able to recover all known CV Candidates
• Found Orbital Period Redback Pulsar
• Detached White Dwarf-Red Dwarf
• First Magnetic He Core WD in GCs
• Many more variables to analyze...

Compact Binaries Surveys

1- SCOVaS: Survey for Compact Objects and Variables

Pichardo Marcano et al. (2021a)

Pichardo Marcano et al. (in prep.)

 

 

 

2- TACOS: TESS AM CVn Outbursts Survey

Pichardo Marcano et al. (2021b)

Compact Binaries Surveys

Outbursts

Pichardo Marcano et al. (2021)

• Precursor
  • TESS (Duffy et al. 2021)
• Echo Outbursts
• DIM with Enhanced Mass Transfer  (e.g. Hameury & Lasota 2021)

TESS AM CVn Outbursts Survey

Pichardo Marcano et al. (2021)

ZTF

TESS

Long-term monitoring

Pichardo Marcano et al. (2021)

• Orbital Periods:
  • 2-minute cadence
• Limits on Recurrence Time
• "Normal Outburts"

Superoutburst duration vs P_orb

Pichardo Marcano et al. (2021)

TACOS Summary

• Precursors and "Normal" Outbursts:
  • Relatively Common
  • Short Duration (missed by ground-based)
• Echo Outbursts:
  • Different morphology
  • Enhanced Mass Transfer
• Superoutburst durations overestimated
• Two new candidate orbital periods
• Color Evolution

Other work with Accreting WDs

• Follow-up eROSITA transient:

• TESS time series analysis

• • Atel: Pichardo Marcano (2020)

  • Paper: Schwope, [...], Pichardo Marcano, et al. (2021)

Caltech

Preliminary Results

M 92

• WFPC-2
• 2008-01-25 to 2008-01-30:
  • 76 Exposures
  • F555W
  • Exp time: 10 s

New Variables in the Core

SX Phe

 

• Good Distance indicator:
  • Strong P-L relation
• Less common than RR Lyrae
• Blue Straggler
  • Product of Binary evolution

P = 1.38 hr

Pichardo Marcano et. al (in prep)

Summary

• BlackGEM:
  • Time-domain astronomy
    • ZTF, ATLAS, TESS, HST
  • Experience Transients
    • Expand my expertise
    • Study 'contaminants'
• Experience Spectroscopy:
  • IFU: MUSE, VIMOS
  • GEMINI

Future Work

NGC 6397

M 92

Spectroscopy (MUSE)

AO Gemini IR

Extra Slides

PTF1 J0719+4858:

• Similar to Dwarf Novae:
  • Hameury et al. (2020)
  • Rivera Sandoval et al. (2021)

Color Evolution

Pichardo Marcano et al. (2021)

TACOS Summary

• Precursors and "Normal" Outbursts:
  • Relatively Common
  • Short Duration (missed ground-based)
• Echo Outbursts:
  • Different morphology
  • Enhanced Mass Transfer
• SO durations overestimated
• Two new candidate periods
• Color Evolution

Long-term monitoring

Pichardo Marcano et al. (2021)

• Orbital Periods:
  • 2-minute cadence
• Limits on Recurrence Time
• "Normal Outburts"

Outbursts

Pichardo Marcano et al. (2021)

Transiting Exoplanet Survey Satellite (TESS)

Caltech

• Porb 20 to ~ 60 minutes (?)

• Superoutburts (SO) and "Normal" outbursts (NO)

  • SO: Superhumps (periodic brightness variation )

• Disk instability model (DIM)

  •  Constant Mass transfer rate

  • Tidal-thermal disk instability model

Outbursting Systems

Empirical Relationships

1. Trec prop Porb^7.35
2. Tdur prop Porb^4.54
3. Delta mag prop Porb
4. Long-term
5. Ground-Based:
   1. PTF
   2. CRTS

Levitan et al. 2015

See also Duffy et al. 2021