Manuel Pichardo Marcano (he/him)

I am a professional Astronomer/Astrophysicists

What does that mean?

I am a professional Astronomer/Astrophysicists

What does that mean?

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Manuel Pichardo Marcano (he/him)

Manuel Pichardo Marcano (he/him)

Manuel Pichardo Marcano (he/him)

Undergraduate (4 years)

Geophysics

Pulsar Timing

• Learned how to Code (Fortran)
• Realized I wanted to become an Astronomer/Astrophysicists
• Apply to a bunch of REU program
• Talk to your professors for research opportunities

Master's Degree (2 yr)

• Learned Python
• Learned how to work with Actual Data
• The first step to becoming an "Observational Astronomer"

This was my idea of what was an Observational Astronomer:

PhD in Physics (6 yr)

• Publish my First Paper
• Went to my First Academic Conference
• Watched Patrick Mahomes play

What does a typical day look like for an astronomer?

How can you get involved?

Citizen Science

NASA Projects:

https://science.nasa.gov/citizen-science/

Variable Stars Citizen Science

Gaia Vari:

https://www.gaiavari.space/

https://www.aavso.org/

Total Solar Eclipse April 8th, 2024

Extra

Underrepresentation of Minorities

Diffraction grating

Surveys

2- SCOVaS: Survey for Compact Objects and Variables

Pichardo Marcano et al. (2021a,2023)

1- TACOS: TESS AM CVn Outbursts Survey

Pichardo Marcano et al. (2021b)

Caltech

NASA

3- MARES: Magnetic Remnants in Symbiotics

Pichardo Marcano et al. (in prep.)

White Dwarfs

Mass ~ 1 M☉

Radius ~ 1 R🜨

Radius ~ 1 R🜨

White Dwarfs

Stellar Remants

NASA

Sirius

White Dwarf

Closest White Dwarf

Sirius A

"Normal Star"

Sirius B

White Dwarf

A Binary White Dwarf

Accreting White Dwarf Binaries

Caltech

Semi-detached systems

Cataclysmic Variables

AM CVn

• Main Sequence Star
• P_orb ~ 80 min - 10 hours
• >1000 in the galactic field
• Predicted large # in old Star Clusters

• White Dwarf/Helium Star
• P_orb ~ 5 - 70 min
• Poorly understood Outburst
• Type Ia SN and GW Sources
• ~70 in the galactic field

Mark A. Garlick

Caltech

Mark A. Garlick

Hydrogen-rich  "normal" Star

White Dwarf

White Dwarf

White Dwarf

AM Canum Venaticorum AM CVn

• White dwarf + White dwarf

• White dwarf + He Star

• Orbital Period: 5-70 minutes

• Rare: 70 Galactic field

Transiting Exoplanet Survey Satellite TESS

TESS Cadence and Coverage

• Primary mission:
  • 2-min selected targets
  • 30-min full-frame images (FFI).
• Extended:
  • 20 sec selected targets
  • 10-min FFI
• Second extended mission
  • 200-second FFI

Disk AM CVns

High state (high Ṁ)

• Hot ionized disk

~20

~10

~40-60 (?)

Low state (low Ṁ)

• Cold stable disk

Caltech

Outbursts

Pichardo Marcano et al. (2021)

SO duration

• Precursor
  • TESS (Duffy et al. 2021)
• 5/6 have Precursor
  • Except ASASSN-14cc

PTF1 J0719+4858

ZTF

TESS

Precursor

Pichardo Marcano et al. (2021)

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
  • Constraint on Trec vs. Porb
• Color Evolution

Cataclysmic Variables

• White dwarf primary

• "Main-sequence" donor

• Roche-lobe overflow

• Accretion disk (non-magnetic)

• Highly Variables:

  • Dwarf novae

    • 2-8 mag outburst

    • 10-100 increase in L

Cataclysmic Variables

R. Hynes

X-ray

Looking of CVs in GCs

NASA, ESA, H. Richer and J. Heyl (University of British Columbia), and J. Anderson and J. Kalirai (STScI)

Finding CVs in X-rays

• Advantages of X-ray Searches:

  • Avoid crowding

• Disadvantages:

  • Small FoV (FUV)
  • Lx ≥ 10²⁹ ergs/s

Summary CVs in GCs

• Few of CVs per cluster

• X-ray biased sample:

  • Lx > 10²⁹ergs/s

• Predicted "Hidden" Population:

  • Belloni et al. (2016, 2017a, 2017b)

• Dearth of DNe:

  • Only 17 confirmed

• Core-collapsed:

  • Bimodal population

• Period distribution?

  • ~15 known periods

All Magnetics ?

See Review by Belloni & Rivera Sandoval (2020) arxiv:2008.12772

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

SCOVaS: Survey for Compact Objects and Variables

Preliminary Results

NGC 6397

• Closest Core Collapse
• Second Closest
  • 2.4 kpc
  • 15 CV candidates
  • 2 Pulsars

Preliminary Results

NGC 6397

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

Preliminary Results

NGC 6397

• 126 Orbits (F336W)
• Lomb–Scargle
• False Alarm Probability < 10^-8
• Bluer than the MS

Preliminary Results

NGC 6397

We haven't found new

X-ray faint CVs

Spoiler Alert!

Other Binaries

Credits: NASA/Rivera Sandoval

Main et al 2018 (Nature)

Redback 'spider' Pulsar

Redback  Pulsar

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
  • Confirmed by Zhang et al. (2022)

Magnetic He WD Candidate

• Binary: Vrad > 150 km/s (MUSE)
• Not Detected in X-rays
  • Lx < 10²⁸ ergs/s
• Not an Roche-lobe filling stripped star
  • M~ 2 x 10^-4 ☉

• 18.4 hours 

Rotational Period

ESO/L. Calçada

 Pichardo Marcano et al. (2023)

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
• First Magnetic He Core WD in GCs
• Second Magnetic WD?
• Many more variables to analyze...

Where are all the CVs?

AM Canum Venaticorum AM CVn

• White dwarf + White dwarf

• White dwarf + He Star

• Orbital Period: 5-70 minutes

• Rare: 70 Galactic field

Finding CVs in X-rays and UV

• Advantages of X-ray Searches:

  • Avoid crowding

• Disadvantages:

  • Small FoV (FUV)
  • Lx ≥ 10²⁹ ergs/s

Summary CVs in GCs

• Few of CVs per cluster

• X-ray biased sample:

  • Lx > 10²⁹ergs/s

• Dearth of DNe:

  • Only 17 confirmed

• Core-collapsed:

  • Bimodal population

• Non core-collapsed:

  • 1 faint population

• Period distribution?

  • 16 known periods

All Magnetics ?

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

SCOVaS: Survey for Compact Objects and Variables

Preliminary Results

NGC 6397

• Closest Core Collapse
• Second Closest
  • 2.4 kpc
  • 15 CV candidates
  • 2 Pulsars

Preliminary Results

NGC 6397

We haven't found new

X-ray faint CVs

Spoiler Alert!

Other Binaries

Credits: NASA/Rivera Sandoval

Main et al 2018 (Nature)

Redback 'spider' Pulsar

Redback  Pulsar

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
  • Confirmed by Zhang et al. (2022)

Magnetic He WD Candidate

• V_rad > 150 km/s (MUSE)
• Not Detected in X-rays
  • Lx < 10²⁸ ergs/s
• Roche-lobe filling stripped star?
  • M~ 2 x 10^-4 ☉

• 18.4 hours 

Rotational Period

ESO/L. Calçada

Please talk to me about:

(Things I want to learn more about)

• Compact Binaries/Binary Evolution:

  • White Dwarfs Binaries and LISA
  • Common Envelope
  • Stripped Stars (e.g. sdB, WR, ...)
  • Products  of Binary Evolution (e.g. Barium Stars, R CrB, ELMs ...)
  • Halo vs Thick Disk Population (Gaia):
• Star Clusters (GCs     ):
  • LISA background
  • WD binaries in GCs (Binary Evolution)
• Time-Series Analysis:
  • Methods:
    • Gaussian Process
      • Flickering/QPOs/Magnetism in Symbiotics
    • Classification (unsupervised):
      • Dynamic time warping/The information bottleneck method
      • Where are all the AM CVns?

Also interested in:

• TESS:
  • Transients
  • Crowding
  • Symbiotics
• Halo vs Thick Disk:
  • Halo CVs
  • Halo AM CVns?

Data from Peters (2008)

Blue Variables

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...

Where are all the CVs?

Preliminary Results

M 92

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

Preliminary Results

NGC 6397

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

He WD Candidate

 Pichardo Marcano et al. (2023)

HACKS CMD

 Data: Libralato et al. (2022)

Also interested in:

• Magnetic White Dwarfs:
  • A Magnetic Extremely Low-Mass WD in a Globular Cluster?
  • Magnetic WDs in Symbiotics from TESS:
    • Spin-up?

Data from Peters (2008)

• 18.4 hours 

• Halo vs Thick Disk:
  • Halo CVs:
    • Not Period Bouncers
  • Halo AM CVns

Pichardo Marcano et al. (2023)

Z And

28 min to 26.7 min in 20 Yr

He WD Candidate

Tracks from Althaus et al. (2009)

0.16 M☉

 0.22  M⊙

0.52 M⊙

• 18.4 hours 

He WD Candidate

Magnetic He WD Candidate

• Binary: Vrad > 150 km/s (MUSE)
• Not Detected in X-rays
  • Lx < 10²⁸ ergs/s
• Not an Roche-lobe filling stripped star
  • M~ 2 x 10^-4 ☉

• 18.4 hours 

Rotational Period

ESO/L. Calçada

He WD Candidate

 Pichardo Marcano et al. (2023)

MUSE spectrum

Data from Husser et al. (2016), Kamman et al. (2016)

• 5.3 hours 

Variable and No Hα Excess

• Not Detected in X-rays
• 0.2 Δmag in F336W
  
• No Hα in Excess
  
• Periodicity

  • 5.3 hours 

Variable WD Candidate

 Pichardo Marcano et al. (in prep.)

HUGS CMD

Data: Piotto et al.(2015)/ Nardiello et al. (2018)

Variable WD Candidate

 Pichardo Marcano et al. (in prep.)

HUGS CMD

Data: Piotto et al.(2015)/ Nardiello et al. (2018)

AM CVn Donors

van Roestel et al. 2022

q = M2/M1

0.0125 < q < 0.18

M2 = Donor

AM CVn Donors

Coleman et al. 2018

0.0125 < q < 0.18

<R_d> ~10¹⁰cm

q = M2/M1

AM CVn Donors

Coleman et al. 2018

0.0125 < q < 0.18

<R_d> ~10¹⁰cm

q = M2/M1

Mass-transfer rates vs orbital period

Mass-transfer rates vs orbital period

Magnetic He WD Candidate

 Pichardo Marcano et al. (2023)

• 18.4 hours

• 0.16 M☉

• 0.24 R☉
• 0.11 Gyr
• Teff 7586 K
• log g = 4.9

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

Compact Binaries Surveys

2- SCOVaS: Survey for Compact Objects and Variables

Pichardo Marcano et al. (2021a)

Pichardo Marcano et al. (2023)

   Pichardo Marcano et al. (in prep.)

1- TACOS: TESS AM CVn Outbursts Survey

Pichardo Marcano et al. (2021b)

Caltech

NASA

• Color Evolution

PTF1 J0719+4858

Pichardo Marcano et al. (2021)

ZTF

SO

NO

SO

NO

rebrightening

rebrightening

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

SDSS J1043+5632

ZTF

TESS

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

SDSS J1043+5632

ZTF

TESS

PTF1 J0719+4858:

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

Color Evolution

Pichardo Marcano et al. (2021)

Accreting White Dwarf Binaries

Cataclysmic Variables

AM CVn

• Main Sequence Star
• P_orb ~ 80 min - 10 hours
• Outbursts:
  • 2-20 days
  • Disk instability model+ (DIM)
• >1000 in the galactic field
• Predicted large # in old Star Clusters

• White Dwarf/Helium Star
• P_orb ~ 5 - 70 min
• Outburts:
  • weeks?
  • DIM?
• ~70 in the galactic field

Mark A. Garlick

Caltech

Color Evolution

PTF1 J0719+4858

• Similar to Dwarf Novae

  • Hameury et al. (2020)

• Similar SDSS J1411+4812
  • Rivera Sandoval et al. (2021)
• Compare to SDSS 1137
  • Rivera Sandoval et al. (2021)

Pichardo Marcano et al. (2021)

SDSS J113732+405458

 Enhanced mass transfer

Rivera Sandoval et al. (2021)

Color Evolution

PTF1 J0719+4858

SDSS J113732+405458

 Enhanced mass transfer

• Similar to Dwarf Novae

  • Hameury et al. (2020)

• Similar SDSS J1411+4812
  • Rivera Sandoval et al. (2021)
• Compare to SDSS 1137/SDSS 0807
  • Rivera Sandoval et al. (2021)

Pichardo Marcano et al. (2021)

Rivera Sandoval et al. (2021)

AM CVns

•  Helium Rich and Know to go into outburts

Normal Outbursts

V803 Cen

• WZ Sge like ?
  • Precursors
  • EMT (Hameury+'20)
  • Massive WD?

• Compare to TCP J21040470+4631129
  • EMT (Hameury+'20)
• Helium "SU UMa"
  • EMT+TTI (Kotko+'12)

AM Canum Venaticorum AM CVn

• White dwarf + White dwarf

• White dwarf + He Star

• Orbital Period: 5-70 minutes

• Rare: 70 Galactic field

Caltech

• P_orb 20 to ~ 60 minutes (?)

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

• Disk instability model (DIM)

  •  Constant Mass transfer rate

  • Tidal-thermal disk instability model

    • SO: Superhumps (periodic brightness variation )

Outbursting Systems

AM CVns

•  Helium Rich and (some) known to go into outbursts

Color Evolution

PTF1 J0719+4858

SS Cyg

Cataclysmic Variable

• Similar to Dwarf Novae

  • Hameury et al. (2020)

• Similar SDSS J1411+4812
  • Rivera Sandoval et al. (2021)
• Compare to SDSS 1137/SDSS 0807
  • Rivera Sandoval et al. (2021)

Pichardo Marcano et al. (2021)

Type of Super Outbursts

Osaki et al. (2005)

High Mass Ratio

DIM

Cataclysmic Variables

• Evolution Superhump

Pichardo Marcano et al. (2021)

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

Caltech

• Porb 20 to ~ 60 minutes (?)

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

• Disk instability model (DIM)

  •  Constant Mass transfer rate

  • Tidal-thermal disk instability model

    • SO: Superhumps (periodic brightness variation )

Outbursting Systems

Place Constraints

Constraint Empirical Relationships

1. T_rec ∝ P_orb^7.35
2. T_dur ∝ P_orb^4.54
3. Δ mag ∝ P_orb
4. Ground-Based:
   1. PTF/CRTS
   2. ZTF
   3. LINEAR

Levitan et al. 2015

See also Duffy et al. 2021

1. T_rec ∝ P_orb^7.35
2. T_dur ∝ P_orb^4.54
3. Δ mag ∝ P_orb
4. Ground-Based:
   1. PTF/CRTS
   2. ZTF
   3. LINEAR

Levitan et al. 2015

See also Duffy et al. 2021

Need detailed short-term variability

Constraint Empirical Relationships

Long-term monitoring

Pichardo Marcano et al. (2021)

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

Type of Super Outbursts

Osaki et al. (2005)

High Mass Ratio

DIM

Cataclysmic Variables

Pichardo Marcano et al. (2021)

See also Duffy et al. (2021)