# Public Data Release Handbook

Note

We are still rolling out the full data release of HSC PDR2 morphological parameters. This page will be updated continuously through the Spring of 2023. If you can’t find the portion of the data-release that you need, please drop us a line!

## FTP Server

All components of the public data release are hosted on the Yale Astronomy FTP server ftp.astro.yale.edu. There are multiple ways you can access the FTP server, and we summarize some of the methods below.

### Using Unix Command Line

ftp ftp.astro.yale.edu
cd pub/hsc_morph/<appropriate_subdirectory>


If prompted for a username, try anonymous and keep the password field blank. After connecting, you can download files using the get command.

### Using a Browser

Navigate to ftp://ftp.astro.yale.edu/pub/<appropriate_subdirectory>

### Using Finder on OSX

Open Finder, and then choose Go → Connect to Server (or command + K) and enter ftp://ftp.astro.yale.edu/pub/hsc_morph/. Choose to connect as Guest when prompted.

Thereafter, navigate to the appropriate subdirectory.

## Hyper Suprime-Cam Wide PDR2 Morphology

### Prediction Tables

The prediction tables are located at the following subdirectories on the FTP server:

• g-band HSC-Wide z < 0.25 galaxies → /pub/hsc_morph/g_0_025/g_0_025_preds_summary.csv

• r-band HSC-Wide 0.25 < z < 0.50 galaxies → /pub/hsc_morph/r_025_050/r_025_050_preds_summary.csv

• i-band HSC-Wide 0.50 < z < 0.75 galaxies → /pub/hsc_morph/i_050_075/i_050_075_preds_summary.csv

The various columns in the prediction tables are described below:

• object_id: The unique object ID for the galaxy. This is the same as the object_id in the HSC-Wide PDR2 catalog.

• ra: The right ascension of the galaxy in degrees.

• dec: The declination of the galaxy in degrees.

• z_best: The redshift of the galaxy. This is the same as the z_best in the HSC-Wide PDR2 catalog.

• zmode: The redshift mode of the galaxy. The two options are specz or photz.

There are multiple columns for each of the three morphological parmaeters: effective radius (R_e) (in arcsec), bulge-to-total_light_ratio (bt), total flux (total_flux) (in ADUs), and mangitude (total_mag). In all the columns below xx refers to the column names mentioned in brackets.

• preds_xx_mode: The mode of the posterior distribution for the morphological parameter. (Recommended)

• preds_xx_mean: The mean of the posterior distribution of the morphological parameter.

• preds_xx_median: The median of the posterior distribution of the morphological parameter.

• preds_xx_std: The standard deviation of the posterior distribution of the morphological parameter.

• preds_xx_skew: The skewness of the posterior distribution of the morphological parameter.

• preds_xx_kurtosis: The kurtosis of the posterior distribution of the morphological parameter.

• preds_xx_sig_ci: The 1-sigma confidence interval of the posterior distribution of the morphological parameter.

• preds_xx_twosig_ci: The 2-sigma confidence interval of the posterior distribution of the morphological parameter.

• preds_xx_threesig_ci: The 3-sigma confidence interval of the posterior distribution of the morphological parameter.

### Posterior Distribution Files for Individual Galaxies

The predicted posterior distributions for individual galaxies are available as .npy files. The files are named as zz.npy where zz is the object_id mentioned in the prediction tables. The files located at the following subdirectories on the FTP server:

• g-band HSC-Wide z < 0.25 galaxies → /pub/hsc_morph/g_0_025/posterior_arrays/

• r-band HSC-Wide 0.25 < z < 0.50 galaxies → /pub/hsc_morph/r_025_050/posterior_arrays/

• i-band HSC-Wide 0.50 < z < 0.75 galaxies → /pub/hsc_morph/i_050_075/posterior_arrays/

You can load the .npy files using the np.load function in Numpy. The array dimensions are as follows:

• 0 → x of radius (in arcsec)

• 4 → y of radius (in arcsec)

• 1 → x of flux (in ADUs)

• 5 → y of flux (in ADUs)

• 2 → x of bulge-to-total_light_ratio

• 6 → y of bulge-to-total_light_ratio

• 3 → x of magnitude

• 7 → y of magnitude

### Trained GaMPEN Models

The trained GaMPEN models are available as .pt PyTorch files. The models are at the following locations:-

Real Data Models

• g-band HSC-Wide z < 0.25 galaxies → /pub/hsc_morph/g_0_025/trained_model/g_0_025_model.pt

• r-band HSC-Wide 0.25 < z < 0.50 galaxies → /pub/hsc_morph/r_025_050/trained_model/r_025_050_model.pt

• i-band HSC-Wide 0.50 < z < 0.75 galaxies → /pub/hsc_morph/i_050_075/trained_model/i_050_075_model.pt

Simulated Data Models

• Simulated g-band HSC-Wide z < 0.25 galaxies → /pub/hsc_morph/sim_g_0_025/trained_model/sim_g_0_025.pt

• Simulated r-band HSC-Wide 0.25 < z < 0.50 galaxies → /pub/hsc_morph/sim_r_025_050/trained_model/sim_r_025_050.pt

• Simulated i-band HSC-Wide 0.50 < z < 0.75 galaxies → /pub/hsc_morph/sim_i_050_075/trained_model/sim_i_050_075.pt

#### Trained Model Parameters

We mention some of the finally tuned hyper-parameters that we used for the above models. Note that while performing inference using the above models, you will need to use some of these parameters.

##### Real Data Models

Parameter Name

Low-z Real Data

Mid-z Real Data

High-z Real Data

model_type

vgg16_w_stn_oc_drp

vgg16_w_stn_oc_drp

vgg16_w_stn_oc_drp

cutout_size

239

143

96

droput_rate

0.0004

0.0002

0.0002

label_scaling

std

std

std

loss

aleatoric_cov

aleatoric_cov

aleatoric_cov

lr

5e-8

5e-8

5e-6

momentum

0.99

0.99

0.99

nesterov

False

False

False

weight_decay

0.0001

0.0001

0.0001

parallel

True

True

True

target_metrics

custom_logit_bt, ln_R_e_asec, ln_total_flux_adus

custom_logit_bt, ln_R_e_asec, ln_total_flux_adus

custom_logit_bt, ln_R_e_asec, ln_total_flux_adus

split_slug

balanced-dev2

balanced-dev2

balanced-dev2

##### Simulated Data Models

Parameter Name

Low-z Sims.

Mid-z Sims.

High-z Sims.

model_type

vgg16_w_stn_oc_drp

vgg16_w_stn_oc_drp

vgg16_w_stn_oc_drp

cutout_size

239

143

96

droput_rate

0.0007

0.0007

0.0004

label_scaling

std

std

std

loss

aleatoric_cov

aleatoric_cov

aleatoric_cov

lr

5e-7

5e-7

5e-7

momentum

0.99

0.99

0.99

nesterov

False

False

False

weight_decay

0.0001

0.0001

0.0001

parallel

True

True

True

target_metrics

custom_logit_bt, ln_R_e_asec, ln_total_flux_adus

custom_logit_bt, ln_R_e_asec, ln_total_flux_adus

custom_logit_bt, ln_R_e_asec, ln_total_flux_adus

split_slug

balanced-dev

balanced-dev

balanced-dev

#### Scaling Data

Note that as mentioned in the Predictions Tutorial, in order to unscale the predictions made using the above models, you need access to the training files.

You can access these files at the following locations using wget:

ftp://ftp.astro.yale.edu/pub/hsc_morph/xxxx/scaling_data_dir/info.csv

and

ftp://ftp.astro.yale.edu/pub/hsc_morph/xxxx/scaling_data_dir/splits/

where xxxx is g_0_025, r_025_050, or i_050_075 for low-, mid-, and high-z real data models respectively; and sim_g_0_025, sim_r_025_050, or sim_i_050_075 for low-, mid-, and high-z simulated data models respectively.

#### Custom Scaling Function

As mentioned in the Tutorials, all the trained GaMPEN models first make predictions in the logit(bulge-to-total light ratio) space. The predictions are then scaled to the bulge-to-total light ratio space using the custom inverse-scaling function defined in /GaMPEN/ggt/modules/result_aggregator.py.

Here, for completeness, we provide the custom scaling function that we used for the forward logit transformation while creating our info.csv files. The only way this is different from the standard logit transformation is that we prevent the function from blowing up for values of bulge-to-total_light_ratio that are very close to 0 or 1.

from scipy.special import logit

def logit_custom(x_input):

'''Handling for 0s and 1s while doing a
logit transformation

x_input should be the entire column/array
in info.csv over which you are applying
the transformation'''

x = np.array(x_input)

if np.min(x) < 0 or np.max(x) > 1:
raise ValueError("x must be between 0 and 1")

if np.min(x) == 0:
min_x = np.min(x[x != 0])